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How did belief in Greek Mythology die out and what replaced them ? | The basic answer for the broader definition of Greek Myth/Religion is Christianity, but I think that broad definition isn't necessarily what most people think of when they say "Greek Mythology" today. The storybook version of 12 Olympian gods and series of concrete stories about each of them never existed. There were always competing or contradicting versions, and that didn't bother the ancient Greeks. In fact, many of the most popular stories are best preserved in their Roman forms by the *Metamorphoses* of Ovid.
It's hard for us to wrap our heads around in a world so dominated by religions like Christianity and Islam that try to define one absolute correct for of the religion, but the ancient Greeks were much more concerned with proper ceremony and practice in the present than which stories and character traits went with which gods. They also had no problem with gods from outside of their pantheon. Some gods only cared about Greece/the Greeks, others were called by different names in other cultures. If they couldn't find an analogue for one of their gods, they were more than happy to believe in a new foreign god and worship with the local traditions when they travelled. That brings me to the really radical change in "Greek mythology."
After the conquests of Alexander his successors carved out kingdoms from Afghanistan to Greece and made plays for power in Sicily and Italy. As Greek/Macedonian culture spread across that huge range, it was in direct contact with more outside influences than ever before. Some foreign, especially Egyptian, gods became some of the most popular and new traditions and stories seeped in. These were gods like Isis, Serapis, and Cybele.
fter Greece was conquered by Rome (a culture that borrowed heavily from Greece, but almost never copied Greek tradition exactly) that process continued to incorporate new religious traditions from across the Roman Empire into the Greeks' traditions. Much like some of the new gods during the Hellenistic period, a few new gods of the Roman period also surpassed the traditional Olympian pantheon in some places. So already by the second century CE you have many foreign cults that coexist with the classical myths, but were also surpassing them in some contexts. It was already a very different environment in Greece than it was in 300 BCE.
Some of the more famous examples include Mithra and Elagabalus. Both were Near Eastern deities picked up by the Roman armies as they marched across the region. Mithra seems to be the more popular one in Greece, but veneration of Elagabalus was found all over the Empire. We don't know much about either. They seem to have existed somewhere between traditional polytheistic religion and henotheism where one god is worshipped and many are acknowledged. Both were linked to the ancient Greek god Helios, but like I said, we don't know much in the way of details about what was really believed.
So finally, I get to the thing that really killed it off. It was just another little Near Eastern tradition that was circulating around the empire, competing for popularity with things like Mithra. The difference is twofold: this one was vehemently monotheistic and caught the attention of enough of the imperial elite, including the emperors. Of course, it's Christianity.
There had been some on and off persecution by the authorities because associations with Juaism and refusal to venerate the imperial cult (ie the deified dead emperors) were both viewed as treasonous. However, by the time Constantine gave official tolerance to Christianity with the Edict of Milan in 313, some estimates suggest that Christians accounted for almost 2/3 of some major cities. It had reached Greece and Anatolia very early on and had a strong foothold there to begin with.
Close to death, Constantine converted officially, and all of his successors were raised Christian. Aside from a brief hiccup where Julian the Apostate tried to turn back the clock with an official canonical form of Greco-Roman paganism, it was a steady uphill climb for Christianity. Each successive Roman emperor tended to enact policy that supported Christianity over traditional paganism. Churches and Christian communities were given state funding over pagan temples, pagans were blocked out of official offices, and emperor Gratian went on a spree of confiscating pagan temple revenues, removed an altar to pagan Victory in the Senate house, and became the first emperor since Augustus not to accept the office of Pontifex Maximus, high priest of traditional Roman religion.
In 318 Gratian and his co-emperors, most notably Theodosius I, issued a decree stating that all of his subjects should follow Nicene Christianity, effectively making Christianity the official religion of the Roman Empire, and establishing an official Christian dogma for that state religion. Theodosius permitted, but did not outright endorse, the destruction of many prominent pagan temples. He ended any remaining legal and official support for pagan institutions.
Beginning in 381, Theodosius engaged in official condemnation and persecution of non-Christian, non-Orthodox beliefs and practices that remained the standard policy for the Roman empire for the rest of its history, right through the Byzantine period. Despite heavy persecution, some pagan beliefs and practices probably survived for a few more centuries in rural or isolated areas, but by 400 or so, it was functionally gone in population centers.
The classical myths hadn't been the sole feature of Greek religion for more than 700 years by the time it was truly gone. In fact, they hadn't even been the most popular option for a few centuries, but ultimately Christianity's strict monotheism ended and replaced belief in classical Greek myths. | [
"Some scholars see a gap between the existing mythical and the new rational way of thought which is the main characteristic of the archaic period (8th to 6th century BC) in the Greek city-states. This has given rise to the phrase \"Greek miracle\". But if we follow carefully the course of Anaximander's ideas, we wi... |
When I am all alone, and there is no noise in the room, and it is all still and quiet, there is a sound in my ears/head that is similar to a ringing of the ears, but it's not quite the same. What causes that? | [Tinnitus](_URL_0_): "the perception of sound within the human ear in the absence of corresponding external sound".
Causes are varied, so check the ~~Zelda~~ link for more on that. | [
"It's like, all the electric wires in the house are plugged into my brain. And every one has a different noise, so I can't think. Some of the wires have voices in them and they tell me things like what to do and that people are watching me. I know there really aren't any voices, but I feel that there are, and that ... |
How was Garibaldi able to conquer Southern Italy with only 1000 or so volunteers? | You're asking a lot of questions, which is understandable; Wikipedia is not a complete source of information by any stretch of the imagination. Let's begin in the beginning.
After the eighth century, Southern Italy was contested three ways between Arabs, the Byzantine Empire, and "Lombards," who were originally Germanic warriors that intermarried and replaced the old Roman "Senatorial Class."
When Charlemagne conquered Italy from the Lombard King called Desiderius, a rump state survived in Southern Italy; Seeing Charlemagne and his army at the gates of his chief city, Salerno, Duke Arechi of Benevento, a powerful and fiercely loyal vassal of the deposed King of Italy (he had married Desiderius' daughter) came to an agreement with Charlemagne. He sent his son Grimolado as a hostage to Charlemagne's court, and in exchange secured the right to continue ruling as Duke in Southern Italy; Arechi was even recognized the rank of Prince. Although culturally active, the Principality of Benevento would be marred by instability, and by the mid 9th century had split three ways: the Duchy of Benevento and the Duchy of Salerno (whose rulers both claimed the title of "Prince") as well as the independent Republic of Amalfi.
Calabria and Puglia, on the other hand, remained Byzantine Military Provinces (called *Thema*) up to the Norman conquest. A vestige of Justinian's reconquest of Italy in the sixth century, they were ruled by an ethnically Greek *Katepano* (Commander) appointed from Constantinople. Because of southern Italy's strong ties to the Greek world, as well as the Byzantine practice of settling soldiers with land, the general picture of this part of Southern Italy is functionally Graco-Latin, leaning more towards Greek at the top of the social ladder, while the bottom would be more Latin.
Sicily, on the other hand, was predominantly under the Abbasid Caliphate by the ninth century. However, when Robert Guiscard (a Norman mercenary employed at the time by the Duke of Salerno) established a foothold in Messina, he revived an old Byzantine title, *Strategos*, for the governor he appointed; the same title that had been used by the Byzantine military governor (who was based in the same city, no less) when Sicily was originally attacked by Abbasids. Curiously, in the County, and later Kingdom, of Sicily the governor of Messina and its surroundings would continue to be called with the Italianized title "Strategoto", derived from the analogous Greek word, meaning that once the Arab-dominated ruling class was removed a Greek substrate must have been present.
Generally, the early history of Sicily saw Greeks, Lombards, and Arabs fighting with each other in every concievable combination. In 1042, Duke Guaimario of Salerno approved the Norman mercenary William Hauteville's plan to seize Sicily from the Arabs, and in return would be made Count of Puglia (should he be able to conquer that from the Byzantines as well). William (helped by his brother) went above and beyond, and used Puglia as a trampoline to take Calabria, becoming the most powerful person in southern Italy in the process. When in 1052 when Prince Guaimario was murdered, the Hautevilles took advantage of the unrest in Salerno to take the city, completing their conquest of mainland Southern Italy on their way to take Sicily.
William's brother Robert (nicknamed, "Guiscard") managed to impose himself as Count of Sicily. His rule was characterized by the unique coexistence of ethnic Arabs, Greeks, and Normans. There were some limitations on this coexistence, but no real "genocide" as you asked about in your question: in the Norman County (later Kingdom) of Sicily, Greeks and Arab landholders were relegated as "Villeins" (the lowest rank of landholder) and were taxed more heavily than Roman Catholics, a conscious decision which encouraged immigration by Northern Italian Lombards, Britons, Normans, and Provençals, and which rapidly diluted the existing Arab-Greek culture.
Norman Sicily has been defined as a society based on "Unequal Coexistence." Although privileged positions were given to Norman, Provencal, Lombard, and Greek immigrants (more or less in that order) tensions between Christians and Muslims would only come to the breaking point in the late twelfth century. Tensions between Sicilian Greeks and the new "Latins" on the other hand, were easily overcome by professing adherence to the Church of Rome, only recently (in 1054) irreparably separated from the Church of the East, in Constantinople. Indeed, Greek Christians (who had in great part welcomed the Normans) played a key role in mediating between the upper class of Latin lords and the subject populations of Muslim serfs (according to Johns J., *The Monreale Survey: Indigenes and invaders in medieval west Sicily*). It's interesting to note how within a generation of the Norman conquest, parish censuses show how serfs whose parents have Arabic names take Greek names; a testament to the dominant "Greek Christian" culture in spite of the new Norman ruling class and the almost entirely Arab administrative bureaucracy, and more importantly, the key role of Greek Churchmen in converting the Muslim population to Christianity.
John Julius Norwich, in his *The Normans in Sicily* puts it this way: “Norman and Lombard, Greek and Saracen, Italian and Jew – Sicily had proved that for as long as they enjoyed an enlightened and impartial government, they could happily coexist; they could not coalesce.” Greek Orthodox inhabitants of Sicily could be expected to be fluent in Arabic, and some Muslims could be expected to be native Greek speakers. However, as with Arabic, Greek language and culture was also rapidly replaced in favor of Latin language and culture in Sicily and indeed all of Southern Italy. If you'd like to learn more, John Julius Norwich wrote a very extensive history of Sicily in two works, one chronicling the Norman Conquest and another on the actual history of the kingdom. Both works have recently been published together as a single work.
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"Having conquered Sicily, he crossed the Strait of Messina and marched north. Garibaldi's progress was met with more celebration than resistance, and on 7 September he entered the capital city of Naples, by train. Despite taking Naples, however, he had not to this point defeated the Neapolitan army. Garibaldi's vol... |
- if hiv can take up to 6 months to show up on a blood test, how do they know donated blood is safe? | They generally eliminate high risk classes from donating blood. There are a lot of reports that confirm that HIV transmits faster from certain ways over others. They make sure to ask people questions about their lifestyle to figure out whether they represent one of those high risk classes.
For example my wife is a veterinarian and over half of her class is unable to donate blood because they handled monkeys.
[In the 80s around 2,000 Canadians were infected from tainted blood when HIV was first becoming a thing](_URL_0_). Today all of the mechanisms that are in place are based on old failed policies. | [
"BULLET::::- Every single blood donation is tested for HIV (the virus that causes AIDS) and Hepatitis B and C. Infected blood is not used in transfusions but tests may not always detect the early stages of viral infection.\n",
"In the US, the Food and Drug Administration requires that all donated blood be screene... |
AMA - 20th Century American Popular Culture | Thank you so much for arranging this very interesting panel!
My question is the following: When did the cinema become a common sight in the towns and cities of the United States? Was it something that was targeted for a specific audience or was it like today where everyone ranging from teenage couples to families can find something to watch (and be entertained by)? | [
"Published in 2009 by W.W. Norton & Company, Dickstein’s cultural history of the U.S. in the 1930s considers the complicated dynamic between art and entertainment in the decade, suggesting that the era produced a wide array of popular culture that shares an interest in how “ordinary people lived, how they suffered,... |
How do you think someone in a coma would react to psychedelics? | [This question was asked a few years ago](_URL_1_) and didn't get much of an answer. I don't know if you'll be able to get much more than that, but good luck to you.
I had a look on Google Scholar for you for any reports linking use of psychoactive or psychedelic drugs with [locked-in syndrome](_URL_2_), [persistent vegetative states](_URL_3_) or [minimally conscious states](_URL_0_). I couldn't find anything, but these aren't my areas of research. | [
"The effects of psychedelics vary widely from one individual to the next, and from one experience to the next. Sometimes individuals under the influence of such drugs do not understand that they have taken a drug and believe that they will never return to their ordinary, sober perception, though some can be reminde... |
When is a species no longer considered invasive? | I don't like the first answer to that question in the link you posted. Invasions happen all the time. In fact, it's why biogeography is such a fun field to get into.
Species expand outwards and encroach on other ranges ALL the time. However, the truth is that the definition gets tenuous. I'll be the one to start a firestorm by defining it in very neutral terms:
A species is an invader if it enters and occupies a niche or habitat it was absent from or never occupied previously. I welcome all debate into this as I know some fellow ecologists will probably double take on that. It's the best I can think of anyway.
So, species ranges are not set in stone and you'll see them in spots on their documented periphery where you never did before. Thus, if you consider Locality A and locality B, Species 1 from Locality A enters Locality B, finds it suitable to live in, and settles. Species 1 is therefore an invader. Species 2 is found in Locality B, but doesn't invade Locality A and stays in B. Thus, for this example, we can decide that Species 1 is an invader in B and a native in A while species 2 is a native to B.
A species can not occupy a niche or habitat if it is not equipped to utilize resources or compete with species occupying them already. No species enters into a habitat without stiff competition from what's there. Thus, the most common invasive species we find today are those who are not only successful in their home niche, but were evolutionarily flexible enough to be able to expand outwards if given just the bare minimum conditions. Thus, this example is a natural invasion and happens all the time, just the scale is small and the effects are not as dangerous as landscape and global transportation of organisms by humans. For a good example of invasive dynamics at small scales, look up Huffaker's famous experiment with mites and oranges. Thus, we define the spatial scale at which a species is native and invasive in the wild.
On to human caused invasions, the effects can be devestating because we transport species across landscapes and natural barriers like mountains, saltwater, deserts, and tundras. For example, carps are established quite comfortably in the United States, even though they are native to China. And it is due to human trafficking that they are found pretty much world wide. Black basses like Largemouth bass and small mouth are so popular around the world for sport fishing, that they've been imported as far as Japan. Red-swamp crayfish are so delicious and economically easy to grow that they are found in Africa... where there are no native crayfish!
When is a species no longer considered invasive? At the appropriate scale. No species is invasive at the global scale, since we all occupy the planet, but it can be at all landscape, ecosystem, community, and population scales. Yes, even within species can be invaders if you think about two genepools and one of them comes to intermingle with the other to make one big genepool. A cool concept actually.
Also, a species is no longer considered invasive *in effects* if you consider the inclusion of that species into the natural processes of the ecosystem. If the ecosystem is sustainable even with the new invader, then you might want to think that the invader is now an important energy component to that system. Humans are the best example. We cut down forests, harvest the oceans. But the ecosystem adapts after so many species leave for other habitats or die off, and the species left behind work with humans to maintain the energy dynamics of the system for everyone's survival. We understand that more than ever.
| [
"Invasive species, also called invasive exotics or simply exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions. The first definition, the most used, applies to introduced species (also cal... |
how'd the yahoo "hacking" happen? | According to [the post from Yahoo](_URL_0_)
> For potentially affected accounts, the stolen user account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (using MD5) and, in some cases, encrypted or unencrypted security questions and answers. The investigation indicates that the stolen information did not include passwords in clear text, payment card data, or bank account information. Payment card data and bank account information are not stored in the system the company believes was affected.
Unfortunately the post does not make it clear if the hashed passwords were salted. If they were not salted it would be very easy for an attacker to find many users that had used common passwords, especially with around a billion to work with. Thankfully there was no credit card information stolen, but with all of the information that was stolen put together and the the likelihood that people will reuse passwords and usernames across multiple sites it could be very dangerous.
Also, [Shellshock](_URL_1_), a security issue with Bash, the command language default on Unix operating systems. Essentially it allowed an unprivileged user to gain privileged access to a system, essentially allowing them to do whatever they wanted. | [
"A simple matter had sparked a controversy over Yahoo!. The controversy was sparked because of Yahoo!'s silence about the data breach. After the servers were hacked, Yahoo! did not mail the affected victims, although it was promised earlier. There was no site-wide notifications about the hack, nor did any victim ge... |
Are there any known examples of jump discontinuities occurring in the natural world, (not related to manmade systems)? | Phase transitions, shock waves, electric/magnetic fields at boundaries where there is a surface charge/current density, just to name a few. | [
"A jumpgate has been discovered in the Typheous system, and eight Earth corporations want to control it. Each of them therefore starts up a branch in the system, and begin to battle it out with the latest in military technology.\n",
"Jumpstyle, originally known simply as jump, was created in Belgium. It was a sho... |
Why don't we and other animals have eyes in the backs of our heads? Wouldn't having a 360 vision be a massive benefit? | Many "prey animals" have upwards of 270 degree vision with eyes on the sides of their heads. Deer, rabbets, chickens.
We have binocular vision to prey better. Most predators have binocular vision. Owls, tigers, men.
Many insects have nearly 360, and most are prey to anything bigger.
Size matters more.
As animals go, humans are pretty big. | [
"Some predator animals, particularly large ones such as sperm whales and killer whales, have their two eyes positioned on opposite sides of their heads, although it is possible they have some binocular visual field.\n",
"Other animals that are not necessarily predators, such as fruit bats and a number of primates... |
Why were there so few German-American organized crime groups? | It's hard to say something didn't happen, but we can say why other groups did turn to organized crime. Ethnic groups who were blocked from traditional employment often attempt to break out and make it by turning to crime. We can see this in the heavily discriminated against groups of the Italians, Irish, Jews, and Black organized crime, but not in the generally accepted Germans. | [
"In Germany federal authorities have largely failed to provide sufficient resistance to ethnic organized crime gangs (German: \"Clankriminalität\") as fear of stigmatizing and discriminating minorities takes precedence. All ethnic crime gangs are collectively treated as organized crime.\n",
"The same large and po... |
Would it be possible for a human to stand on an asteroid or comet as it speeds through space? | If the asteroid in question had enough mass for it's gravity to hold you down, yes. | [
"If such a crew is to be summoned to a distant asteroid, there may be less risky ways to divert the asteroid. Another promising asteroid mitigation strategy is to land a crew on the asteroid well ahead of its impact date and to begin diverting some its mass into space to slowly alter its trajectory. This is a form ... |
why do we find the natural human odor to be so offensive? are there other animals who are put off by the smell of their own species? | Well, that's not "natural human odor" you're smelling. What you're smelling are actually mostly the chemical byproducts of bacteria eating all the oils and things in your sweat.
These bacterial byproducts are actually some of the same chemicals that make some cheese smelly and even some of the same ones that make rotting flesh smell the way it does. | [
"There is also a specific anosmia to the odor in some humans; they are unable to smell specific odors, but have, otherwise, a normal sense of smell. However, this should, by no means, be regarded as indicative for being labeled as a pheromone, as it is true of over 80 olfactory compounds.\n",
"The role of smell h... |
Any good book on history of education? | Hi, a while ago I commented on a similar question. [You could have a look here](_URL_0_), perhaps it could be useful to you as well? | [
"\"The Education\" is an important work of American literary nonfiction. It provides a penetrating glimpse into the intellectual and political life of the late 19th century. The Modern Library placed it first in a list of the top 100 English-language nonfiction books of the 20th century.\n",
"The history of educa... |
Why are salts of hydrochloric acid and organic bases called "hydrochlorides" instead of "chlorides"? | Acid-base reactions don't necessarily result in water being produced, that is only true for the simplest case of Arrhenius theory in which the acid always provides a proton and the base a hydroxyl group. A more general theory of acid base reactions is [Bronsted theory](_URL_0_), which still defines an acid as a group that can release a proton, but a base is any species that can accept a proton.
Take the example of pyridine mentioned in the Wiki article. What is happening is that when you react pyridine with hydrochloric acid, since the amine moiety (the nitrogen atom) is basic, it will become protonated (the hydrogen will tack on) to create C5H5N-H^+ and then the chlorine anion will serve as the counterion to maintain charge neutrality, so that in the end you will have the salt C5H5N-H^+ Cl^- . | [
"Rather than being neutral (as some other salts), alkali salts are bases as their name suggests. What makes these compounds basic is that the conjugate base from the weak acid hydrolyzes to form a basic solution. In sodium carbonate, for example, the carbonate from the carbonic acid hydrolyzes to form a basic solut... |
security codes on credit cards | It makes it harder to use stolen credit card data for online purchases without the physical card. The 3 digit code is not stored on the cards magnetic strip, it's only printed on the card itself, so if the card's data is surreptitiously stolen using a card skimmer, they don't get the code, and theoretically it should be impossible to use the card for online purchases (assuming the online store in question requires the code). | [
"Both of these standards are maintained and further developed by ISO/IEC JTC 1/SC 17/WG 1. Credit cards have a magnetic stripe conforming to the ISO/IEC 7813. Many modern credit cards have a computer chip embedded in them as a security feature.\n",
"The card security code is typically the last three or four digit... |
I've heard there was hand-to-hand fighting in Stalingrad. Is this true? If so, why weren't guns sufficient? | Hand-to-hand can be something of a misnomer, in that it is often used as an example of hyperbole to indicate the ferocity of urban combat, and is not necessarily literal.
That being said, urban warfare gets up close and personal, and Stalingrad is in the running for most brutal urban combat of all time, and there are examples of journals from both sides where the authors specifically mention and describe hand-to-hand fighting in close quarters.
Edit: I will note that the primary source letters and journals with which I'm familiar were translated into English, and were exclusively from the Soviet perspective. I'm not sure hand-to-hand is a figure of speech in Russian the way it is in English. | [
"The Stalingrad counteroffensive, Operation Uranus, exposed the Red Army's urgent need for mobile heavy guns. Primary targets for these guns were German fortifications in and around Stalingrad. At the time Soviet front-line ground units did not possess sufficient firepower to deal with pillboxes and other fortifica... |
Was Greek civilization derived from Egypt | Civilisation is one of those loose terms that, the more we think about it, the harder it is to define. I'm assuming you mean the general sense of identity/values/aesthetics/social structures and so on that we consider to be 'Greek.' The answer really isn't simple.
Firstly, to say there was a single Greek civilisation is a bit over simplistic. When most people think of Greece they think of Athenians, with their forums and philosophers, but Athens was not all of Greece nor was it often the most important. Sparta is the obvious counterpoint, but there's also Corinth, Thebes, and hundreds of other city-states with their own social structures and values. The point being that ancient Greeks were unified by a shared language (although divided by dialect) and a general region, but were not some unified cultural group by a long shot.
Okay, so let's just take a general Athenian-esque sense of Ancient Greece. Did it draw from Egypt and the Near-East? Yes, absolutely. Herodotus thanks Egypt for teaching Greece things like geometry and mathematics. Did Greece take everything? No, of course not. Its language, Athenian democracy, Greek hoplite warfare, literary/oratory works like those of Homer, or great architectural achievements like the Parthenon. Egyptians and Babylonians didn't make those. Greeks did.
There's also the fact that 'philosophy' is a very broad term. French post-modernism, Chinese Confucianism, and European renaissance humanism are all philosophises of their own but are very distinct things. Humans seem to be hard-wired to question their own existence and societies. The Egyptians were among the first, but it's by no means uniquely theirs. 'Architecture' is a similarly diverse thing. Peru's Machu Pichu is a feat of architecture just like Rome's Colosseum or Beijing's Forbidden Palace, but each one is a unique reflection of their societies and time periods using different material and methods. The same is true for Greek architecture as opposed to Egyptian or Babylonian - the Pyramids are not the Parthenon.
Cultures are not discrete nor do they exist in a vacuum. Each one builds on what came before and redefines it for its own needs. Cultural transmission is not a case of X culture meeting Y and taking all of Y's ideas. Y's ideas might take root in culture X, but culture X's unique perspectives and uses can and almost always will produce an entirely new thing Z. Think of how tea is a cornerstone of British culture despite originally being Indian, or how rice has integrated itself into Persian cuisine despite only making it to the region in the 13th century or so. Just because something comes from somewhere else, that doesn't mean a culture can't make it their own. The premise that if one culture found something first then it's forever theirs is just not appropriate. By that logic, everything is African since the basic tenants of society like language and fire was first utilised by the earliest humans spreading from the continent.
I know this answer has been more broad reaching that just Greece of Egypt, but I think taking a step back and addressing the basic assumptions implicit in the question are important.
As for some basic things that were original? I mentioned a few, but we can list more. Greek mythology, perhaps the first histories as we'd understand them from those like Herodotus or Thucydides, democracy, the Greek language and its derivatives, theatre, winches and cranes, etc etc. Of course, these ideas have changed over time. Modern democracy is not the same as ancient Athenian democracy, but that's the whole point - humanity builds on what came before and what came from elsewhere. We always have and we always will. | [
"Archaeological evidence suggests that the history of the ancient Greeks in Egypt dates back at least to Mycenaean times ( 1600-1100 BC) and more likely even further back into the proto-Greek Minoan age. This history is strictly one of commerce as no permanent Greek settlements have been found of these cultures to ... |
how can a baseball player throw 95 mph baseball when a boxer's top punching speed is around 25 mph? | Because the speed of a pitch comes from the whip of the arm accelerating the ball. The punch is just arm movement. The two are not connected when it comes to speed. | [
"Scientists contend that the theoretical maximum speed that a pitcher can throw is slightly above . Beyond that the pitcher would cause himself a serious injury. There is no doubt that a pitcher who can throw at 100 mph+ is rare, with only a small handful of pitchers every generation being capable of this feat.\n",... |
when and why will the current tech boom end? what are the implications for the overall economy? | "Tech" is a very big field with many sub genres if you like. The 70-90s boom was the personal computer, 00s-10s was the the internet era and to a certain extent it's still going. The next few years will see lots of wearables, IoT and all things 3D printing related. We expect to see interesting developments and changes in how computing as a whole is done.
It's also important to realise that tech is in everything and spills out to almost every other field from medicine to aviation.
I don't see the popularity of tech going down anytime soon as it has become a fundamental tool for facilitating almost everything in modern society | [
"A report published in 2013 looked at the effect of new technologies on the structure of the labour market, with repetitive jobs being replaced by automation. It predicted that over two decades, 45 percent of all jobs in the United States were at risk of replacement. A report published in early 2016, \"Industrial R... |
How long did it take to Christianise the people of Denmark and other parts of the Viking world (Norway, Sweden, Iceland etc)? | It depends on the region; The Jelling Stone in Denmark announcing the establishment of Christianity as the religion by Harald was still significant even if it didn't mean the whole country was converted yet. As did the Icelandic þing decision of 1000 and Saint Olaf's supposed completion of christening of Norway a few decades later. The Swedes were supposedly still largely pagan according to Adam of Bremen in his own day (1070s) and the last concrete mention of pagan resistance there would be the martyring of Saint Botvid by a pagan in 1120. Adam of Bremen also claims fringe areas of Denmark - Bornholm and Blekinge as not having been converted properly until their bishop missioned there in the 1060s. However, Adam has a bias in wanting to hold forth the importance and relevance of the missionary work done in the ecclesiastical province of Hamburg-Bremen that he represented and there's a commonly-held interpretation that he neglected or minimized the contributions made by Anglo-Saxon and Irish missionaries. Adam was not a first-hand witness to conditions in Scandinavia either (and Orderic even less so).
Archaeology actually pushes the dates back a bit. Christian burials first turn up in Bornholm already in the late 900s. The excavation of Kata Farm and other sites in Sweden now show that at least the elites in Götaland were converting in that same late-900s time frame as the core areas of Denmark, and the same goes for Østfold and Rogaland in Norway. Whereas areas like Trøndelag, Agder, northern Norway and the inner parts of eastern Norway converted later, as did Svealand in Sweden. Evidence shows rapid changes towards Christian burial practices in the 11th century in Norway. Even in Sveland's Uppland, historians tend to side with an earlier date than a later one; it was probably mostly Christian by the 1080s. Adam's claim that Emund the Old (circa 1050s) neglected Christianity could be interpreted as Adam's judgement on Emund's tolerance of paganism. It's been suggested the traditional date of 1120 for Botvid's martyring may be a bit late too.
Of course by Christian burial practices we primarily mean east-west oriented graves and the abandoning of cremation. Needless to say, that doesn't necessarily mean the buried were completely Christian. (Burials in churchyards was also a thing that would come later) But Scandinavia was likely almost completely converted by 1100, and in that century Christian institutions were strengthened considerably and what holdouts may have existed would have the thumb-screws tightened by the fact that things like inheritance rights became contingent on conversion. Although law codes we have from the 13th century, like Gulathingsloven, ban pagan activities, there's no concrete evidence of such activities still happening in that period. (one might compare to Magnus Erikssons Country Law of 1340 which finally banned thralldom in Sweden but entered into force something like 70 years after the last mention of anyone owning a thrall)
As I said in [a post yesterday](_URL_0_), the nationalists/romantics of the 19th century really wanted to believe paganism had survived longer than it actually likely did, because they'd adopted the view that pre-Christian beliefs were a core part of national identity. (and that crowd is still around although not so represented in academia anymore) But we don't know that any actual Viking Age Scandinavians felt that way. If it was such a core part of their identity, one would perhaps expect more resistance than we know of. On the contrary, it's been argued (e.g. in _Skiftet_) that resistance to conversion may have been primarily rooted in opposition to the associated political and social changes, not the faith itself.
The Baltic States and Finland were converted later (and the Scandinavians played no small part in those Baltic Crusades), and those were much more isolated parts of Europe. Scandinavia had frequent cultural contacts with the continental and southern Europe for a millennium before the Viking Age ended. As for Delumeau, his ideas that most European weren't 'really' Christians (not just the north) doesn't have that much support. Although it's based in the correct observation that the average masses did not view nor practice Christianity the same way as the priests and educated classes, judging that this means that these people weren't Christian is anachronistic because it's based on later standards. These people regarded themselves as good Christians and by the standards of their time, _were_. It (and associated "two-tier" models like Muchembled's) have also been criticized since the start for being overly simplistic and creating a false dichotomy because there was in fact significant interplay between the 'low' and 'high' religious traditions. E.g. the medieval canonization of saints was often little more than an official sanction of a popular veneration that'd started spontaneously.
Anyway, Denmark was mainly Christian well before Canute IV, in fact most of Scandinavia probably was by that point. Anyway, this is a pretty brief post, but to mention some sources and further reading:
Nora Berend (ed), _Christianization and the Rise of Christian Monarchy: Scandinavia_, Central Europe and Rus' c. 900–1200, Cambridge University Press, 2007
Anders Winroth, _The conversion of Scandinavia: Vikings, merchants, and missionaries in the remaking of Northern Europe_, Yale University Press, 2014
Sten Tesch (ed), _Skiftet - Vikingatida sed och Kristen tro_, Artos & Norma, 2017 | [
"The history of Christianity in Norway started in the Viking Age in the 9th century. Trade, plundering raids and travel brought the Norsemen into close contacts with Christian communities, but their conversion only started after powerful chieftains decided to receive baptism during their stay in England or Normandy... |
why do games nowadays get sold at normal price unfinished? is it just for money, or is the gaming industry creating such massive games they can't release all the content at once? | I'm 33 years old and was heavily involved in gaming when I was a teenager. I'm not the most OG guy around, but I remember a "back in the day" story or two.
You are remembering with rose colored glasses what "then" was like. Back then games were routinely released with game killing bugs. While we did not see the DLC for content that should of been there by default, we saw a lot more of the "this game cannot currently be played, wait for the 2.0 patch".
In addition, expansions were often after thought content. So you'd pay nearly full price for 2 new weapons (and one of them uses the model of an old weapon) and a handful of new levels. $40 please. | [
"However, many users stated that this is the biggest push factor to inflate, as the sellers now demand higher prices before selling an item (in order to make up for the loss of in-game money through tax system). Also, some users state that the inflation will eventually stop without the interference of the game deve... |
How does a bit in a computer turn on or off (1 / 0) without something to do it manually? | To add a little context to it computer memory used to be wires and magnets as in [this picture](_URL_0_). So imagine on the left the wires are 1, 2, 3, 4, etc and at the bottom the wires are a, b, c, d, etc. If you run current through wires 1 and a the memory location 1a would be on, or 1.
As /u/ramk13 noted today it is done with capacitors and transistors but the idea is basically the same, just a lot smaller and faster.
| [
"So far the article has covered how to turn bits on and turn bits off, but not both at once. Sometimes it does not really matter what the value is, but it must be made the opposite of what it currently is. This can be achieved using the codice_21 (exclusive or) operation. codice_21 returns codice_1 if and only if a... |
Did Sweden out of fear cooperate/facilitate the invasion and conquest of Norway by Nazi Germany? | There's a lot of myths about this and I've [previous debunked](_URL_0_) some of them, for more reading. So, to try to keep this short:
**Invasion of Norway**
Sweden most certainly did not aid the _invasion and conquest_ of Norway. Sweden was no more aware of the impending invasion than Norway was, so they couldn't if they wanted to (which they did not).
What happened here was that _after_ the invasion and occupation of Norway was completed, the Nazi government demanded that unarmed German troops who needed medical care and others on leave, would be allowed to pass from Norway through Sweden on train to and from Germany. This "transiting" was a violation of neutrality; although a smoewhat slight one; the former transiting was explicitly permitted under the Hague Convention, the latter was not. In a few cases, trains with sealed boxcars that the Swedes could reasonably assume had arms did pass through Sweden, and the most flagrant violation was the 'Midsummer crisis' when the Swedish government acquiesced to allow some armed German troops to pass through Sweden from Norway to Finland, for the purpose of defending Finland against the Soviets.
So Germany made no use of Sweden whatsoever to 'take control' over Norway. It had some use of Sweden in maintaining the occupation. But in the greater scheme of things it's not so clear how great the impact really was. It's not likely it would've strained Germany so much to ferry the troops over to occupied Denmark instead. The main issue was likely the safety of their troops; such ferries being potential targets for allied air raids.
The main reason the transiting is well known is not because of its great significance to the war effort, but because it was intensely unpopular in Sweden at the time as it was a violation of neutrality that helped a country most Swedes hated in an occupation they hated. It remains a well-known fact if not one of the most well known facts in Sweden, together with the Swedish iron trade with Germany. Probably _too_ well known (as historians have pointed out), the public perception of Swedes is that Sweden helped Germany much more than they actually did.
Your post here certainly raises the bar to new heights of absurdity. though.
**Trade**
Germany had been Sweden's largest trading partner since well before a unified Germany even existed. International law does not ban neutral parties from trading with belligerents though, and when the war broke out, Sweden made a War Trade Agreement with Germany and the Allies in December 1939 that set quotas for trade with Germany in strategic goods such as iron ore and ball-bearings, which were set _below pre-war levels_. Trade in other commodities did go up; Sweden had no choice in that; the Gulf of Finland was mined (and Sweden was hostile to the Soviets anyway after the outbreak of the Winter war) and so was Skagerrak. Germany only allowed a few ships to pass each month, and those were allocated for the most desperately needed goods. Sweden did try to secretly aid the allies here by charging the British less for Swedish ball-bearings (on which they were critically dependent for aircraft engines) than the Germans. Which is actually a violation of neutrality. Ball bearing exports to Germany ceased completely in 1944, and generally exports to Germany were ramped down as the war progressed and Sweden's negotiating position improved.
The Swedish economy did **not** benefit from the war. It's not just false but completely absurd to even believe the GDP would increase by 20% in a time when the country was suffering severe shortages of all import goods but particularly fossil fuels, on which it was dependent for heating, steel production and vehicles. A significant portion of vehicles had to be converted to run on wood gas. Rationing was in effect for sugar, coffee, salt, meat, and other consumer goods. Sweden had received thousands of refugees from neighboring countries; such as the 70,000 'war children' from Finland, which demanded resources. Sweden's conscript-based armed forces were at full mobilization; over a million men out of a 6-million population were drafted into service. Resources were poured into arms production.
I don't see how it is reasonable to believe that Sweden's GDP grew by a whopping 20% in that time period. It most certainly did not; Sweden's economy suffered from the war. In year 2000 SEK values, the GDP per capita was 56.6k SEK in 1939, _dropped_ over 10% to 50.0k by 1941, and recovered to 53.8k by 1945. ([numbers from _URL_1_](http://www._URL_1_/htmldatatest2/index.html))
> they(Sweden)committed the great crime of appeasement ?
Did Sweden commit a 'great crime'? You're taking the two most well known actions of Sweden during the war - transiting and the iron ore trade - and trying to reduce the entirety of what happened to that. Which is to ignore entirely the actions the Swedish government took _against_ the Germans, who they in fact were against. Those are not as well known because unlike the transiting, they were _not_ known at the time. They were highly secret for fear of provoking a German invasion. Sweden's most egregious violation of neutrality was in fact in Norway's favor; starting in 1943, the government secretly trained over 15,000 Norwegians as 'police' to form an army unit of the exile government, which later participated in the liberation of Finnmark Fylke. This was so secret, even the Swedish military leadership wasn't briefed on it until 1944. It is a more severe violation of neutrality than the transiting of unarmed German troops, and a voluntary one at that and not one that Sweden was coerced into.
Likewise, while the Swedish public were well aware of the German troops moving to and from Norway on trains, they were wholly unaware that the Swedish government had allowed the OSS and Norwegian government-in-exile to transit thousands of Norwegian resistance fighters who'd fled to Sweden over to Britain. And more generally the government was aware of the Norwegian Resistance was active on Swedish territory. It wasn't known until decades later that the Swedes broke the German codes during the war and shared some of that information with the Allies. And there are many other things.
But basically you're taking a point of Swedish wartime self-criticism here and casting it as the defining event of Swedish-Norwegian post-war relations, and it certainly was not. Casting it as Sweden enriching itself at Norway's expense by helping the Nazis is a _huge_ distortion of history. | [
"Overall the operation appeared to meet few of its initial aims. The political approach did lead to an increased discussion amongst the lower levels of Swedish officialdom as to the possibility of an invasion in Norway. However, it failed to convince the higher levels of government (with the exception of Nordenskiö... |
need some physics help to explain why or how this works? (xpost from r/lifehacks) | > ...mainly just the idea as to whether the flower pots actually do help generate more heat and faster.
Definitely not. The flower pots are only insulating the heat given off by the candles, so it won't dissipate as fast (the same way a thermos works, essentially). Since the room is so small, and his desk is right next to the "heater", it could make a difference. | [
"Following Latour (Latour, 2007: 139), the materiality-turn is related to \"the way we move knowledge forward in order to access things that are far away or otherwise inaccessible\" (materiality) or \"the way things move to keep themselves in existence.\" We propose to call this 'matter-iality', to emphasise how th... |
why is it that when you quit smoking you get sick and cough so much. | Nicotine is a physically addictive drug meaning that your body developed a physical dependence on the drug being in your system.
Without the nicotine your body starts to go through withdrawal symptoms until your nicotine dependence is gone. | [
"Like other physically addictive drugs, nicotine addiction causes a down-regulation of the production of dopamine and other stimulatory neurotransmitters as the brain attempts to compensate for the artificial stimulation caused by smoking. Therefore, when people stop smoking, depressive symptoms such as suicidal te... |
If the sun suddenly disappeared from the center of the solar system, how long would it take the Earth to freeze and for life on Earth to die off? Minutes? Days? Weeks? | There would be no gravitational interaction with the Sun, for the planets to orbi, so they would continue in a straight line in the velocity direction of when the gravitation interaction stopped, they would no longer be "falling" towards the Sun. Though if any of the planet's got close enough to eachother they could create their own system - such as an Earth > Jupiter system as opposed to an Earth > Sun system. Hopefully we would avoid crashing through material from the asteroid belt.
As far as what would happen to life:
_URL_2_
_URL_0_
_URL_1_ | [
"In roughly 5 billion years, the Sun will cool and expand outward to many times its current diameter (becoming a red giant), before casting off its outer layers as a planetary nebula and leaving behind a stellar remnant known as a white dwarf. In the far distant future, the gravity of passing stars will gradually r... |
Why is it that I can see both Venus and Jupiter in the night sky at the same time? | You may enjoy [this.](_URL_0_) | [
"Because the inner moons of Jupiter are in synchronous rotation around Jupiter, the planet always appears in nearly the same spot in their skies (Jupiter would wiggle a bit because of the non-zero eccentricities). Observers on the sides of the Galilean satellites facing away from the planet would never see Jupiter,... |
how is the price of a book determined? | Supply and demand. Books with small publishers and high demand are expensive. Famous authors are expensive. Books that are considered up-and-coming stars are given better jackets and priced higher than new books that the publisher has deemed serviceable but not amazing. However, new books cost more than old books because there is more demand for them. | [
"Book prices generally depend on the demand for a given book, the number of copies available for purchase, and the condition of a given copy. As with other collectibles, prices rise and fall with the popularity of a given author, title, or subject.\n",
"The price of an item is also called the \"price point\", esp... |
Why are face transplants so rough? | There are so many nerve endings. Not like with most plastic surgery, where it's one area of the face that is fixed. This is an *entire face*.
I would assume there's a lot of tissue damage/tissue death involved as well. It's just a really difficult task. | [
"An alternative to a face transplant is facial reconstruction, which typically involves moving the patient's own skin from their back, buttocks, thighs, or chest to their face in a series of as many as 50 operations to regain even limited functionality, and a face that is often likened to a mask or a living quilt.\... |
How effective were ironclad warships? | As /u/Superplaner pointed out, the lack of many notable clashes in the short span where Ironclad Battleships were the Queen of the Seas makes judging their effectiveness a little hard to manage. One of the few we have is the Battle of Hampton Roads, and all the evidence points to the Union Fleet's Dahlgren guns being especially ineffective for the purpose of armor penetration, while other guns available at the time might very well have torn the CSS Virginia to pieces.
I got into a friendly debate on just this matter only last week in another thread, and while I don't think we reached a truly satisfactory conclusion to it, [the chain may at least highlight some of the issues](_URL_0_).
As you can see, it was mainly centered around the states of the Royal Navy and American Navy in the mid to late 1860s, so is not terribly applicable for later developments seen in the 1880s and 1890s, when breech-loaders in turrets became the norm. One of the most notable incidents we have of wood v. iron is the Battle of Hampton Roads, and all the evidence points to the Union Fleet's Dahlgren guns being especially ineffective for the purpose of armor penetration, while other guns available at the time might very well have torn the CSS Virginia to pieces. As I quoted in the linked thread, this section from a British publication in 1869 entitled "Our Iron-clad Ships" has this to say on the merits of American guns vis-a-vis British:
> The Americans, as is well known, have followed a different system in the development of their naval guns, preferring to have a heavy projectile of large size with a comparatively low velocity, instead of an elongated projectile of less weight moving at a high velocity. The American system has been well termed the 'racking' or "battering" system, in opposition to our own method, which is known as the "punching" system. In carrying out their plan, the Americans have adopted guns of 9, 11, 13, 15, and even 20-inch calibre, and guns of 25-inch calibre and upwards are said to be contemplated. These large guns are almost without exception of cast iron, and nearly all are smooth-bores throwing cast-iron spherical shot. [...] Great differences of opinion prevail with respect to the comparative merits of our own and American guns. [...] Captain Noble shows that the American 15-inch gun, charged with 50 lbs. of our powder, and throwing a spherical steel shot weighing 484 lbs., would fail to penetrate the Lord Warden's side at any range' while our 9-inch 12-ton gun, with a 43-lb. charge, would send its 250-lb. shot through her at a range of 1000 yards. He also states that the 15-inch gun would not penetrate the 'Warrior' beyond a distance of 500 yards, while our 7-inch 6-ton guns (weighing about one-third as much as the 15-inch gun) would do the same with a charge of 22 lbs. of powder and a 115-lb. shot ; and the 12-ton gun would penetrate up to 2000 yards. It must be remembered that, instead of the steel shot hero supposed to be used with the 15-inch gun, cast-iron shot are really employed by the Americans; and this tends to increased superiority in our guns as respects penetrating power. There can be little or no doubt that the American guns have greater battering power; the real question at issue is, as before stated, the relative merits of penetration, and racking or battering. | [
"They were very large and fast warships for their time, displacing over 15,000 tons at full load; could make , while could achieve . Other ironclads of the era could not make more than . Their high speed, powerful main battery, and thin armor protection has led to many naval historians to characterize the ships as ... |
At roughly what time in history did European weapons become technologically superior to those found in the rest of the world? | So, apparently the people who answered you removed all their comments. So I'll try and give you some basic guidelines, but this is pretty far from my expertise:
1) First of all, the level of technology did and still does vary drastically across the world.
An important thing to realise is that technology is not just knowledge, it's also the infrastructure to use that knowledge. People like the steppe nomads wouldn't have much advanced technology, because the climate they lived in and the way of life that climate required did not support the development of the complex chains of trade and industry necessary to create more advanced technology. Not because they'd be too dumb or culturally backward to learn it if necessary. *(EDIT: or maybe it's more complicated than that, see /u/siqr below)*
Also, while I'll leave the why to actual experts, size matters. Eurasia+North Africa was one continuously connected cultural sphere, and because of its size it was generally technologically ahead of the unconnected Americas.
2) Second, technology is not one behemoth. Different people could excel in different things. When it came to shipbuilding I believe the Europeans were ahead of the rest of the world from around the 16th century. But part of this was simply that only the Europeans were interested in building large complex ocean-going vessels. For example the Japanese build a Western-style ship under Jesuit guidance, and [sailed to Mexico in 1614](_URL_0_). But never had any interest in trading with and exploring the world like the Europeans did.
3) This also moves to the heart of your question. In general, this question is difficult to answer because for a long time what was one of the centres of technology in the Eurasian sphere, East-Asia, was simply not interested in developing the same technologies Europe did. If you're talking general scientific knowledge, then assuming there weren't any highly developed scientific communities I'm not aware of, Europe began pulling ahead from the start of the Renaissance, and you could probably jot down 1600 as a year when Europe's scientific knowledge is the best. The reason I'm picking it is because around then we have the invention of the microscope and telescope, which are the easiest examples I could think of where Western inventions are reaching new horizons in human knowledge.
4) But if you want a clear and simple answer regarding European military superiority: The moment when Europe gained a truly vast and insurmountable lead over the rest of the world is the Industrial Revolution. It is no coincidence that the [Opium Wars](_URL_1_), the first time China was humiliated by a Western power, happened in 1839. Before the industrial revolution, even though the Europeans were ahead in certain respects, they were not so far ahead that China could not kick them out of their own country if they pleased.
Afterwards, European powers could do essentially what they want, as it was virtually impossible for an unindustrialised nation to withstand an industrialised one. | [
"Along with advancements in communication, Europe also continued to advance in military technology. European chemists made new explosives that made artillery much more deadly. By the 1880s, the machine gun had become a reliable battlefield weapon. This technology gave European armies an advantage over their opponen... |
what are the major differences between aerobic and anaerobic exercise? | Aerobic exercises are often classified as cardio and endurance work outs. They focus on doing light exercises for long periods of time to help the blood flow and help muscle groups learn to work for extended periods of time. This is what's most often recommended for people who are working out just to lose weight, because it consumes lots of calories. Aerobic exercises literally mean "pertaining to the freedom of oxygen" meaning that you are getting enough oxygen through your system to keep going for long periods of time.
The most simple aerobic exercise is jogging/running, not sprinting, not dashes, but taking the dog for a walk or going for a jog around the block. Other ones include steppers, light swimming and cycling. These are designed to get your heart racing, and leave you breathing heavy, but not cause you to pant, heave or feel dizzy.
Anaerobic exercise means "pertaining to the lack of oxygen" these are shorter, more intense work outs designed to build muscle, speed and strength. The lack of oxygen to your body causes lactic acid build up, which is what causes "the burn". If you are trying to do a power workout and don't feel it, you may need to step it up, but in contrast, if you are running and feel it, take a breather.
Some widely done anaerobic workouts are push-ups, sprints, bench press, etc. Which are done in sets which are subdivided into reps. Sets should not exceed a minute or two, with a break in between.
In all, it depends on what you want to do. If you just want to trim some fat, throw on the running shoes and start running, but if you want to build muscle you grab some weights and start pumping. | [
"Aerobic exercise (also known as cardio) is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process. \"Aerobic\" means \"relating to, involving, or requiring free oxygen\", and refers to the use of oxygen to adequately meet energy demands during exercise via aerobi... |
please explain me why some people believe the world trade center catastrophy was a conspiracy act | No one here actually explained anything about why people believe its a conspiracy act. I, myself, **do not** believe any of this, but this is what is said. Whether any of it is true, I do not know.
1. There have been only 6 times in history that a steel building has fallen due to fires. 4 of them happened the WTC buildings. 2 were poorly constructed buildings.
2. Building 7 was located across the street from the twin towers, and also fell due to controllable fires apparently. It was hit with debris from the towers collapsing. Going back to #1 this is hard to believe given that no plane hit this building. Would a fire get spread when a building falls and rubble hits another building? WTC 7 is also said to have been the control center where all the planning was done and was taken down to destroy the evidence. Some of the floors were government controlled.
3. If you watch the videos, you can see people standing in the holes left by the plane. If people were there, the fire must not have been that strong. Combine that with #1 and #2.
4. The designer of the towers said specifically that both buildings were designed to withstand 2 planes hitting them.
5. The head of security at the WTC buildings was the younger brother of George W. Bush, whose 2 year contract ended on the day of the attacks. Also someone claimed a multimillion dollar insurance policy afterwards.
6. Some people looked at the moment the buildings were collapsing and noticed small explosions that looked like controlled demolition .
7. The Pentagon was said to have been hit by the same type of plane, a 767, yet there is no lawn damage in front of the building at all. Also some windows right next to the damaged portion of the building are in tact. Also the hole in the pentagon is smaller the width of the wings of a 767.
8. A passport was found for Mohammed Atta, one of the attackers outside the rubble of the collapsed towers. A paper passport from inside the plane, that exploded with enough fire and heat to bring down a building survived after the towers collapsed.
9. The steel after the towers collapsed was quickly destroyed. People would have liked it to have been saved so it could have been studied to find the cause of the collapse.
I'm sure there are more, but thats is all I can remember off the top of my head.
| [
"The most prominent conspiracy theory is that the collapse of the Twin Towers and 7 World Trade Center were the result of controlled demolitions rather than structural failure due to impact and fire. Another prominent belief is that the Pentagon was hit by a missile launched by elements from inside the U.S. governm... |
My uncles were born identical twins, yet their personalities seem to contrast each other. Is this a known thing? | If they're identical (monozygotic) twins then technically they were the same ball of cells at some point. Monoamniotic/monochorionic monozygotic twins split at around day 10ish post-fertilization (just past the blastocyst stage), but most other twins split prior to that. Depending on when you define the start of life, that may or may not qualify for 'one person split in two.'
But in all seriousness, there's no mechanism for different personality traits to be apportioned out to each twin. It's just the interplay of various nature/nurture effects. | [
"Conjoined twin brothers are born in a royal family, but are separated at birth. Though they are twins, one has a blood disorder so his skin discolors and his left arm is paralyzed. Years later they discover each other and unite to free their kingdom from the traitors.\n",
"In terms of appearances, the twins are ... |
if older cartoons and animated movies were drawn by hand, how did they get the coloring so even and clean, unlike paintings for example? | You mean how they stay perfectly inside the lines? It's because the sheets the animation is drawn on are transparent. They draw the lines on one side, then paint on the backside, so even if they're off slightly, filmed from the front, the color is perfectly inside the lines.
If you mean how uniform the colors are... You can make paintings like that too if you want, but painters often go for more nuance, shading, gradients, textures, etc. So they don't paint it as flat, uniform spans of color. | [
"Ub Iwerks adapted xerography to eliminate the hand-inking stage in the animation process by printing the animator's drawings directly to the cels. The first animated feature film to use this process was \"One Hundred and One Dalmatians\" (1961), although the technique was already tested in \"Sleeping Beauty\", rel... |
why does tea taste sweeter after it cools down? | You generally tastes less when drinking really hot things or really cold things, partially due to how fast you tend to move it to parts of your mouth that are less sensitive, and others are signals being mixed with how hot/cold/pain you are feeling. | [
"Sweet tea is tea that is brewed very strong with a large amount of sugar added while the tea is hot. The mixture of sugar and tea is then diluted with water, served over ice, and occasionally garnished with lemon. Sometimes the diluted mixture is allowed to cool to room temperature. Other times the sugar and tea m... |
What would happen if two faults on opposite sides of a tectonic plate shifted simultaneously? | First, the Cascadia subduction zone is on the western edge of the North American plate, but the New Madrid seismic zone is an intra-continental feature, i.e. it is in the middle of the North American plate. The eastern edge of the North American plate is the [Mid-Atlantic Ridge](_URL_1_).
Going with the spirit of the question though, the short answer is nothing different than if the two earthquakes happened at different times. We can look at a [simulated scenario for a magnitude 9 event on the Cascadia subduction zone](_URL_0_) and see that the area that experiences shaking, while certainly large on a societal scale, is small compared to the entire plate. This is because seismic waves dissipate as they travel outward. An earthquake releases a set amount of energy (this amount of energy is what the magnitude is measuring) that is released as seismic waves. As those waves expand out, roughly as a half sphere from the earthquake location on a fault plane, the amount of energy gets spread out so the intensity of shaking decreases. Thus, by the time you're a few 100 km's away, let along on the other side of a plate, the earthquake waves are detectable by a seismometer, but certainly not felt. So, if you had two simultaneous earthquakes on either side of the North American plate, the only effect might be the weird behavior of a seismometer that happened to be positioned such that the arrival time of both earthquakes were exactly the same.
Obviously from a societal perspective, two large events simultaneoulsy in the same country would have lots of effects in terms of resource deployment, etc, but I think you were more asking about the geology aspects of things. | [
"Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. The sides of a fault move past each other smoothly and aseismically only if there are no irregularities or asperities along the fault surface that increase the ... |
canadian's election are really close. can you explain what we should know? (young guy that knows nothing and want to make the best decision) | Read through the party platforms and websites to see which party you most agree with.
Personally I won't vote conservative, because they have blocked research scientist from speaking about publicly funded research results without political approval.
They also closed many research libraries, getting rid of decades wortn of research data, including climate data, and made stats-can useless for econimic planning. (Can you tell I don't like them?)
| [
"\"Choosing Wisely Canada\" leads an international community, made up of nations who are implementing similar programs in their respective countries. At present, this community includes representation from Australia, Austria, Brazil, Denmark, England, France, Germany, India, Israel, Italy, Japan, Netherlands, New Z... |
why can't we build a car that generates its power from the wheels turn like a windmill | Because energy transfer isn't perfect, and the energy you'd expend getting the wheels to turn is WAYYY more than the energy you'd get back trying to use the spinning wheels to turn a generator.
| [
"On the ground, the propeller and rotor are stopped and power is diverted to the wheels, allowing it to travel as a three-wheeled car. Unusually, it leans into turns like a motorcycle, a solution pioneered by the Carver vehicle, also produced by a Dutch company.\n",
"Electric motors, when used in reverse function... |
In medieval Europe how often would you encounter people who carry either a sword or bow? | Medieval Europe is a vast area and time. People you could meet in England in the 1100s would be different than France in the 1250s, and Italy in the 1300s. Can you narrow it down a bit? | [
"BULLET::::- Spadonari di Venaus: Sword dance from Venaus in the Val di Susa done for the feast of San Biagio. Four men clothed in a fastastic imitation of medieval warriors perform with large two-handed swords. The dance lasts about an hour and has only a few figures: raising the sword in salute, circling the swor... |
why are illicit drugs cut with dangerous chemicals? | When you're making drugs "at home' (ie - not a professional lab), you tend to cut corners and not buy everything from the most reputable chemical suppliers. Maybe you need a strong acid, why not grab battery acid or concrete cleaner? A strong base means you use lye-based drain cleaner. A solvent has you use gasoline.
Since there's no real standards or testing, these things get left in there. You then have anti-drug propaganda giving it the scariest possible description when they say what it is. | [
"Historically, chemicals critical to the synthesis or manufacture of illicit drugs are introduced into various venues via legitimate purchases by companies that are registered and licensed to do business as chemical importers or handlers. Once in a country or state, the chemicals are diverted by rogue importers or ... |
Why does the temperature drop just before sunrise? | I'm not sure what you mean. Excluding outside factors like cold fronts, the temperature doesn't suddenly drop just before sunrise.
Just before sunrise is the coldest part of the day because cooling takes place throughout the night while the sun is not up (again, excluding fronts), but there's no sudden drop just before dawn. | [
"Temperature inversions occur most frequently along coastal areas bordering large bodies of water. This is the result of natural onshore movement of cool, humid air shortly after sunset when the ground air cools more quickly than the upper air layers. The same action may take place in the morning when the rising su... |
How Do I find out who is buried on my parents' old property when some of the graves are marked only with stones? | Not asking you to dox yourself at all, but depending on the county it might be worth contacting the county historical society and/or the local newspaper, to see if they have archives going back to the early era of when the area was settled. If I remember correctly, UNC in Chapel Hill has a newspaper archive, and some of the older newspapers in the state have microfilm going back farther than you would think and from predecessor papers as well. (I worked at the Wilmington *Morning Star/Star-News* for awhile out of college and our archives were back to the 1860s.) If you can get an idea of which family owned the land, you may be able to research tax bills or something similar to see what (and who) they owned. | [
"The oldest recorded stones in the cemetery have been there since the early 1800s. Some graves have no headstone and there are no records of who is buried there, just a little X marking a burial spot. The most common symbols found on the headstones are religious crosses. The two mausoleums people visit are the ones... |
Was there ever a more global language than English? | English is widely spoken throughout the world, but isn't nearly as dominant as you might think. It's second to Mandarin in terms of total speakers, and Spanish (a very global language), Arabic, and Russian aren't very far behind. A solid tip in the economy that lasted a few generations could totally upset our perception that English is the language of business in favor of, say, Mandarin. We have never had a more communicative, networked planet, and no other language has enjoyed this advantage. | [
"Modern English, sometimes described as the first global lingua franca, is also regarded as the first world language. English is the world's most widely used language in newspaper publishing, book publishing, international telecommunications, scientific publishing, international trade, mass entertainment, and diplo... |
What are the origins of playing cards? | Follow-up question:
How did certain cards in various games gather their names, such as the left and right "bauers" of Euchre or the "vixer" and "old lady" of Solo?
If I understand correctly, the games I gave as example are historically of German origin, which could have a role in the naming of the specific cards. In fact, "Bauer" means farmer in German, but how did the cards get these names? | [
"Playing cards may have been invented during the Tang dynasty around the 9th century AD as a result of the usage of woodblock printing technology. The first possible reference to card games comes from a 9th-century text known as the \"Collection of Miscellanea at Duyang\", written by Tang dynasty writer Su E. It de... |
what happens to fines paid to government? | Broadly speaking, it's treated as income. In that respect, you can think of it like cutting Uncle Sam a check; it's no different than paying taxes.
It might help to think of the government^1 as a big corporation: there's a highly visible point person, a 538-person board of directors, and a whole bunch of subsidiary corporations. They're all owned by the same company, they all answer to the same CEO, but they all do different things and keep track of their own business — including what they make and what they spend.
Each individual government agency has its own budget; each agency is responsible for keeping tabs on how much money comes in and how much comes out. Fines are generally paid to their relevant agencies — the DOJ would impose criminal and civil penalties, while regulatory agencies like the SEC might also impose their own fines.^2 Those incomes are accounted for in each agency's budget as a separate line item.^3 As for what the agency does with it then? Well, it's kind of up to them; after all, they're the ones who "made" the money. Usually, though, the money will stay within the agency in order to fund its operations.^4
Some specific fines are earmarked for special purposes: criminal fines and penalties are earmarked to go towards the [Crime Victims Fund](_URL_1_), a rather large^5 fund used to compensate victims of crimes.^6 The decision of what to do with the money is really on an agency level, but usually it will go to agency operations.^8
Lastly, it's worth noting that all of these supplemental sources of income are just that: supplemental. Taxes, in their various forms, make up about 91% of all federal revenue, with the bulk of that coming from income and payroll taxes. ([Here](_URL_4_) are some pretty graphs for that!)
******
^1 This is all for federal information. I presume state-level budget management is much the same. State agencies rarely levy massive fines like the DOJ does, but of course state budgets are proportionally smaller.
^2 Many agencies have the power to assess fines for violations of their rules, and I would speculate that most rule violators would rather pay a fine than take it to court and *then* pay a fine. DOJ and SEC are just the poster children for throwing down billion-dollar bills.
^3 Literally! You know how much the government loves paperwork, so you can bet your tax return it's all out there... somewhere. They key is finding it. [Here](_URL_3_) is a set of high-level budget spreadsheets which contain some examples of literal line items for different incomes.
If you take a look at the [Receipts](_URL_0_) document, you can see how the various agencies track their money. In that document, you can see that rows 149–46 represent receipts for the DOJ — and since the DOJ doesn't tax people, all of their money comes from fines and fees. 140 and 143–46 represent fee income, while 139 and 141–42 represent fines.
Various other agencies also have more interesting fees. Line 187 represents assets the Treasury seized from Iraqis — and you'll note that, farther over to the right, that only happened in FY 2003 and 2004. Big settlements might have their own line items; line 195 is the EPA's income from the Exxon Valdez settlement fund.
^4 The exception, of course, being the IRS. They're in the business of making money for everyone else to spend it.
^5 In the [above-linked spreadsheet](_URL_0_), you can see this line item on 142. According to [Wikipedia](_URL_1_), the CVF is currently sitting on about $4B.
^6 More information about the CVF, including their specific financial breakdown, is available [online](_URL_2_). I should note here that, as a general rule, victims of crime can also usually file a civil lawsuit for compensation; the CVF is designed as a gap-filler to provide compensation when the criminal^7 cannot.
^7 Well. Since the civil burden of proof is preponderance, but the criminal standard is of course beyond a reasonable doubt, you can win a civil lawsuit even if a person was not convicted of the crime... but that's a bit beyond the scope of this explanation.
^8 Agencies can't rely on fines for any significant part of their operating budget, of course; they're irregular incomes. Nevertheless, it's reasonable for an agency to expect a range of income based on those fines and to budget around that. Billion-dollar windfalls are just that: windfalls. | [
"One common example of a fine is money paid for violations of traffic laws. Currently in English common law, relatively small fines are used either in place of or alongside community service orders for low-level criminal offences. Larger fines are also given independently or alongside shorter prison sentences when ... |
I read that caffeine in coffee has a half life of about 4 hours. It's this true? If so, why dies it only decay at this rate after the coffee is brewed? | 4-5 hours. The half life is only in regards to the metabolic half life inside the body. A lot of enzymes break down caffeine into other compounds and this process takes time. Some is also expelled through the urine.
Natural degrading of compounds does not happen in the same way. It is a totally different process and it usually takes way longer depending on the enviroment. A dry coffee bean will not lose its caffeine so easily. A wet one however would be subject to bacterial processes. Or one in a very hot place could destroy the caffeine gradually though heat. Or pure caffeine in sunlight could slowly break down the molecular bounds. Some compounds can resist enviromental hazards better than others and some break down quite quickly if they are not kept in an ideal enviroment. Caffeine is on that side of compounds that can take a beating. | [
"The structure of caffeine allows the molecule to pass freely through biological membranes including the blood-brain barrier. Absorption in the gastrointestinal tract reaches near completion at about 99% after only 45 minutes. Half-life of caffeine for most adults is between 2.5 and 4.5 hours when consumption is li... |
How can Orcas jump so high? | It's all about velocity, the faster you can approach the surface of the water, the higher you can jump. However it's not an issue of being better swimmers in general, sharks are neutral buoyancy, orcas are positive buoyancy. This means orcas store energy as they dive, and this gets converted into velocity as they ascend. It makes sense from a survival perspective, sharks don't have to surface to breathe, but if orcas were neutral buoyancy and overestimated their dive endurance, they'd drown. Similarly, but less extreme, if sharks were positive buoyancy, they'd have to waste energy to maintain their depth. | [
"Taiwan serows can jump as high as 2 m and run as fast as 20 km per hour. Among all mammals in Taiwan, they are the best high jumpers. They can be found at an elevation as low as 50 meters, but are mostly seen at 1000 meters and as high as 3500 meters. Their habitats include conifer forest, mixed broad-leaved fores... |
how do the rsa securids work? | Imagine you had two matched devices that generated a series of numbers, 1 every minute, based on a secret formula. You give me one, and keep one for yourself. Later on, I text you, but you aren't sure that it is me, so you ask for the number on my device. If it matches yours, you can be pretty sure it is really me.
That's basically what is going on. The secret formula is designed so that every device can have its once unique version, and that is it is very, very hard to figure out the formula from just the numbers. One device is your key fob, and the other is a program running on the computer you are trying to connect to. This way, even if someone gets your password, they still need the device to log in. | [
"RSA SecurID, formerly referred to as SecurID, is a mechanism developed by Security Dynamics (later RSA Security and now RSA, The Security Division of EMC) for performing two-factor authentication for a user to a network resource.\n",
"RSA is most known for its SecurID product that provides two-factor authenticat... |
why are the french riots with the yellow vest protestors not being reported at all in u.s. media? | A combination of the fact that many people in the US don't care about foreign affairs to begin with and don't understand the reason for the Yellow Vest protests / riots and are therefore not interested, and that even if people did understand what the protests were about, they've been going on for so long that the media would have a hard time marketing it as clickable material.
The conspiracy part of me thinks it's because France is a NATO ally and revered democratic nation and the media doesn't want to glorify mass protests against a publicly elected government. | [
"Earlier in the week, France's highest court denied a request to ban police from using \"flash balls\" or \"defensive ball launchers\", known as LBDs, that shoot rubber projectiles, which have been blamed for a number of serious injuries. French Interior Minister Christophe Castaner admitted in media interviews tha... |
during the war of the currents, tesla and edison battled over superiority between alternating current (ac) and direct current (dc). why is alternating current regarded as more superior than direct current? | It is not really superior. Automobiles use direct current.
The one really important difference up to now is that transformers can be used to step up and down the voltage with alternating current.
At the power plant the voltage is stepped up tremendously to be carried on high overhead wires. High voltage means low current. Low current means more power transmitted over same size wires with less loss due to resistance.
The voltage is stepped down before use in residential and most commercial buildings. Only alternating current can do this using transformers.
There may also be advantages in industry where triple phase alternating current can be made available.
Direct current is actually less dangerous if people connect across the voltage. | [
"In the US the competition between direct current and alternating current took a personal turn in the late 1880s in the form of a \"War of Currents\" when Thomas Edison started attacking George Westinghouse and his development of the first US AC transformer systems, pointing out all the deaths caused by high voltag... |
Are there any measurable differences between two hydrogen atoms? | No. :)
That's a quite significant feature of quantum mechanics. They are completely indistinguishable. And this is a relevant feature when doing calculations in thermodynamics (more precisely in statistical mechanics). | [
"A single hydrogen atom can participate in two hydrogen bonds, rather than one. This type of bonding is called \"bifurcated\" (split in two or \"two-forked\"). It can exist, for instance, in complex natural or synthetic organic molecules. It has been suggested that a bifurcated hydrogen atom is an essential step in... |
a breakdown of the marvel universe leading up to avengers: age of ultron. | They were once all separate heroes but they were eventually all recruited by S.H.I.E.L.D., a US government agency dedicated to detecting and neutralizing threats, both on earth and elsewhere.
It is a lot to go into so I agree with homeboi in saying check out /r/marvel or /r/marvelstudios | [
"Avengers: Age of Ultron is a 2015 American superhero film based on the Marvel Comics superhero team the Avengers, produced by Marvel Studios and distributed by Walt Disney Studios Motion Pictures. It is the sequel to 2012's \"The Avengers\" and the eleventh film in the Marvel Cinematic Universe (MCU). The film was... |
Is CBD oil effective at treating anxiety/depression? | Neuroscience PhD here.
It might be useful for anxiety, but the evidence is nowhere near as clear as people are making it out to be in this thread. More importantly, the side effects and long term effects of chronic is are completely un-studied.
If anxiety is inhibiting your ability to live the way you would like, please see a doctor. I promise that the century of research on the treatment of anxiety will serve you better than trying CBD oil. | [
"Emerging evidence suggests a possible role for CBT in the treatment of attention deficit hyperactivity disorder (ADHD); hypochondriasis; coping with the impact of multiple sclerosis; sleep disturbances related to aging; dysmenorrhea; and bipolar disorder, but more study is needed and results should be interpreted ... |
How did hunting wild animals in Africa change after the introduction of firearms? | Well, first I should note that there was quite a bit of variation. Firearms were being traded to the states of West Africa in the early 1600s, but in interior Central Africa they were still fairly rare and recent introductions in the 1830s. By the same token, use of firearms for hunting varied in different societies.
I'll also note that although the question specifically asks about hunting, firearms were also sought for use in warfare, and many African kings/chiefs were quick to appreciate the military applications. Furthermore, the practice of hunting and specialized hunting fraternities have been seen as having application as training for warfare, even before the introduction of firearms.^1
Though many scholars will point out that the firearms that Europeans traded to Africans in the 18th and 19th centuries were either worn out, outmoded, or otherwise of low quality.
In the Grassfields area along the modern day Cameroon-Nigeria border, flintlock muskets known as Dane guns were traded from the port at Calabar, and were used in warfare and ceremonial functions into the 20th century. Quoting Jan-Pierre Warnier-^2
> According to many informants, guns were seldom used in hunting. Instead, traps nets and spears were used. They only exception may have been that of the leopard- the noblest and most valued game. Many oral accounts report leopard-hunting with guns. However, the actual tactics used in such hunts is not clear. It might be the leopard, once sighted, was lured into attacking a group of gunmen. But even this way of hunting would have been highly dangerous because of the risk of misfiring, though the discharge of an 11 or 12 gauge smoothbore at close range must have been quite effective at stopping a leopard in full _URL_0_ may be that hunters were willing to run high risks to win the rewards associated with the killing of a leopard. Often, it was the gift of a wife by the chief- an invaluable reward in a society where titled men monopolized the women and forced many junior men to remain bachelors for life.
In Central and Eastern Africa (DRC, Tanzania, Zambia), the introduction of firearms was intimately tied to trade in Slaves and trade in Ivory.
Though on the other hand, Warnier also mentions that percussion guns began to be introduced to the region between WWI and WWII, and that flintlock owners had local blacksmiths turn their guns into percussion guns, making them much more reliable and better hunting weapons.
Among societies in Central Africa like the Luba or the Lozi, access to firearms was a symbol of elite status. Guns were procured by long-distance trade, either from Angola through Ovimbundu traders, or from the Swahili coast through Swahili or Nyamwezi trade caravans. The early-mid 19th century saw an expansion of trading networks from the coast deep to the interior of the continent. As I noted above, in 1830 firearms would have been a recent introduction among the Lozi or the Lunda, and there were initially few, and a chief's prestige would be reflected in the number of firearms or even cannons they could display.
At the same time, firearms were deeply connected to the trades in ivory and the trade in slaves. In this era, Nyamwezi and Swahili trader-adventurers like Mirambo, Msiri and Tippu Tip were establishing what I would call "warlord states" in eastern and southern DRC and in central Tanzania, relying on musket armed followers to enforce their usurpation, but also to collect ivory for trade to the coast, or else enforce tribute from local hunters.
This intrusion of Big Men in mid-nineteenth century Central Africa also had profound effects on societies outside of these warlord states. To quote David Gordon-^3
> Ivory became the symbol of the new ruling class, the most prestigious and valued trading item. Warlord chiefs demanded all or a significant portion of ivory from the hunt or employed their own hunters to procure tusks. Indeed, the definition of chieftancy revolved around the ability to impos claims for tribute in ivory....
> Guns were used to procure both slaves and ivory. But it was especially with the ascendance of the ivory trade that guns became a necessary factor of production. Guns were increasingly used to hunt elephants. The hunting of elephants had previously been undertaken by brave men organized in guilds with specialized techniques that included trapping, poisons, and specially manufactured spears. But this changed in the second half of the century. Renowned Chikunda and Bisa elephant hunters gained access to or began to manufacture primitive guns and abandoned their old hunting techniques. they had little choice if they were to compete with the gun-wielding followers of coastal caravans. When, for example, Tippu Tip's followers encountered herds of elephants, they could slaughter 'countless numbers' of elephants.
> But the use of guns to kill elephants was only one aspect of the connection between guns and ivory. The export of ivory became linked to a violent regional trade in slaves. Although exhausted and famished slaves were not effective porters for ivory, the slave and ivory trades developed together as predominantly male ivory hunters desired slaves, often women, as worker and as concubines. The Lunda-Chokwe in the west of the region, for example, purchased female slaves from the Ovimbundu caravans that reached the interior and previously supplied slaves for the Atlantic trade. In exchange they sold ivory destined for the international markets. Farther north, the Kuba ppurchased slaves for ivory. Chikunda hunters in the east also purchased slave women to expand their lineages.
As guns flowed into the region, the earliest European explorers often remarked about how guns quickly depleted the local game population. For instance, Emil Holub visited the Lozi in 1875 and witnessed a royal hunt where he says perhaps 10,000 shots were fired. By 1886, the next Lozi king Lubosi Lewanika forbade the use of guns during the annual royal hunt.^4
Similarly, while living among the Kololo 1853, David Livingstone wrote in his private diary that their recent adoption of firearms to hunt elephants would mean "very soon, none will appear in this part of the country. They retire before the gun sooner tan any other animal". ^5 His prediction was borne out, since the ivory trade in that region of Malawi was exhausted soon after.
Incidentally, with greater European presence in the colonial era, some hunting safari expeditions were seized upon by missionaries as opportunities for evangelization. These hunting expeditions could take a crude form of humanitarian relief, as food providing expeditions in time of local famine. In such circumstances, missionaries could present a successful hunt as a homily on God's gracious provision of food in time of need.
In other circumstances, missionaries armed with the latest firearms could be called upon to use them for the protection of their mission station or local communities against man-killing predators.^6
In Southern Africa, Griqua and Khoikhoi groups introduced firearms to the highveld in the 1820s and 1830s. Many Tswana and other Ngoni chiefs were quick to appreciate the military application of firearms, reasoning that through the getting of firearms, they would become militarily superior to their neighbors and equal to Griqua and whites. The Tswana were also quick to appreciate the effectiveness of firearms for hunting, which made up an essential part of Tswana food strategy until the 20th century.
As in Central Africa, the ivory trade was deeply tied to the trade in firearms. But, in the specific context of Southern Africa, firearms could come from British or Boer traders. By the 1870s, firearms had so proliferated among the Xhosa, the Sotho and the Tswana that Cape Colony officers fighting in the Ninth Cape-Xhosa war (1877-79) and the Sotho Gun War (1880-81) would complain that their foes had superior rifles than their own troops. Additionally, the Gun War was fought over Cape Colony efforts to disarm the Sotho, ending in a de-facto Sotho victory.
Similar settler unease would lead Cape Colony officials to demand Tswana disarmament in 1895. However, Tswana chiefs supported by London Missionary Society missionaries resisted these demands, arguing that firearms had become 'vital to their customary economic activity of hunting'.^7
All of that was a long-walk to say that firearms became a vital part of Tswana hunting strategy and led to a loss of traditional hunting techniques within 60 years of their introduction in Southern Africa.
---
Sources!
1) "The Shirts that Mande Hunters Wore" by Patrick Mcnaughton in *African Arts* Vol 15, no 3 (May 1982) pp54-91
2) *The Cameroon Grassfields Civilization* by Jean-Paul Warnier. pp 65
3) "Wearing Cloth, Wielding Guns: Consumption, Trade and Politics in the South Central African Interior during the Ninteenth Century" by David M Gordon in *the Objects of Life in Central Africa* pp 30
4) *The Gun in Central Africa: A History of Technology and Politics* by Giacomo Macola pp53-72
5)"Reassessing the Significance of Firearms in Central Africa: the case of North-Western Zambia to the 1920s" by Giacomo Macola in *Journal of African History* vol 51 no 3 pp 311
6) "Fishers of Men and Hunters of Lion:British Big Game Hunting in Colonial Africa" by Jason Bruner in *A Cultural History of Firearms in the Age of Empire* pp 60
7) "Firearms in South Central Africa" by Anthony Atmore, J. M. Chirenje and S.I. Mudenge in *Journal of African History* Vol 12 no 4 pp 550 | [
"As former European colonies in Africa gained independence, safari hunting on the continent began a slow decline due to resource mismanagement and political factors. This, in turn, led to a decline in interest in big bore rifles and cartridges used to hunt dangerous African game species. However, by the 1980s Afric... |
what is this warm feeling that starts from the top of my face and goes down towards my body. | Are you an alcoholic by any chance? | [
"Hot flashes, a common symptom of menopause and perimenopause, are typically experienced as a feeling of intense heat with sweating and rapid heartbeat, and may typically last from two to thirty minutes for each occurrence, ending just as rapidly as they began. The sensation of heat usually begins in the face or ch... |
Why do some stars produce four lines that protrude from the star whenever a photograph is taken from them? | This is actually because the telescope that images the star has a secondary mirror that is held in place with four support beams, and that causes an interference pattern that looks like what you're describing. [See here](_URL_0_) | [
"Star trail photographs are possible because of the rotation of Earth about its axis. The apparent motion of the stars is recorded as mostly curved streaks on the film or detector. For observers in the Northern Hemisphere, aiming the camera northward creates an image with concentric circular arcs centered on the no... |
how is it possible that the world collective debt is bigger than world collective wealth? can't we just annul all of the debt that shouldn't be there and go on? | I think that debt IS wealth. If you got rid of the debt, it would remove all the wealth, because the wealth is made up of receivables. That’s one reason why you wouldn’t get a lot of support for this idea from the wealthy. | [
"There is much debate about whether the richer countries should be asked for money which has to be repaid. The Jubilee Debt Campaign gives six reasons why the third world debts should be cancelled. Firstly, several governments want to spend more money on poverty reduction but they lose that money in paying off thei... |
How long does it actually take to form a 'habit'? (Or, is there any truth to the '21 days to form a habit' axiom?) | Habit formation for eating, drinking, and exercise behaviors [has been shown to vary greatly](_URL_0_), taking anywhere from 18 to 254 days. Moreover, in this study, it tended to follow an asymptotic curve, and "the median time to reach 95% of asymptote was 66 days."
While this isn't neuroscience, the study nonetheless suggests that the time it takes to form a habit does not follow some axiom or absolute rule.
EDIT: Incidentally, the source of the 21 day thing is *Psycho-cybernetics* by Maltz (1960). | [
"There is a theory that it takes an average of 66 days to break a habit. The amount of time it takes to break a habit is generally between 18 and 254 days. This should often be repeated once or maybe twice depending on what the habit is, something small like chewing fingernail should only have to be done once. Larg... |
In medicine can 400mg vs. 600mg of some medicine actually mean they are stronger, not just quantity ? | The activity of the drug molecule is unchanged.
I think the biggest concern is accidental overdose - doubling up on a 600 mg pill has a bigger impact than doubling up on a 400 mg pill.
On the flip side of things, I can see 3x 400 mg pills dissolving much faster than 2x 600 mg pill, even though the total amount is identical. However, unless we're talking about time-release formulations, it's unlikely that the solvation of the pill is the rate-limiting step in absorption. | [
"At the same time, only limited number of the middle-weight compounds with a molecular weight from 500 to 2000 Da is used as the therapeutics or is now under study as potent chemical compounds for drug therapy and diagnostics.\n",
"Solubility class boundaries are based on the highest dose strength of an immediate... |
how does an old hospital get sanitized before being turned into another kind of institution? | Would I be correct in understanding that you feel hospitals are DIRTIER than restaurants?
This seems to be a pretty strange thought, could you explain why you believe there needs to be extra steps taken other than the cleaning they do anyway? | [
"A hospital is an institution for healthcare typically providing specialized treatment for inpatient (or overnight) stays. Some hospitals primarily admit patients suffering from a specific disease or affliction, or are reserved for the diagnosis and treatment of conditions affecting a specific age group. Others hav... |
Is there ever a case where a noble gas does react
with something? | Sure. It's more common for the ones with higher atomic number. The outer electrons are shielded by the inner ones, so they're more free to form bonds.
Wikipedia has its own article on [noble gas compounds](_URL_0_) | [
"Unlike noble gases, an inert gas is not necessarily elemental and is often a compound gas. Like the noble gases the tendency for non-reactivity is due to the valence, the outermost electron shell, being complete in all the inert gases. This is a tendency, not a rule, as noble gases and other \"inert\" gases can re... |
Why will two pendulum clocks mounted on a common wall synchronise? i.e. How does coupled oscillation work? | The second pendulum will make the wall move slightly, this movement is transmitted to the first pendulum. It's broadly like [two pendulums joined by a spring](_URL_0_) (a coupled oscillator), but with the wall playing the role of an extremely stiff "spring".
The fact that pendulums are "inanimate" has *absolutely* no bearing on anything. Also, I don't know how you're linking this subject with "the healing nature of sleep". | [
"The cause of this behavior was that the two pendulums were affecting each other through slight motions of the supporting mantlepiece. This process is called entrainment or mode locking in physics and is observed in other coupled oscillators. Synchronized pendulums have been used in clocks and were widely used in g... |
Why wasn't Australia conquered and split by European powers as Africa was? | You may find this thread useful, particularly the response from /u/agentdcf:
_URL_0_ | [
"With the exception of further Dutch visits to the west, however, Australia remained largely unvisited by Europeans until the first British explorations. John Callander put forward a proposal in 1766 for Britain to found a colony of banished convicts in the South Sea or in Terra Australis to enable the mother count... |
why can't spinal discs be "re-hydrated" later in life? | If your doctor didn't explain why, get a new one. He/she obviously doesn't care | [
"This water loss makes the discs less flexible and results in the gradual collapse and narrowing of the gap in the spinal column. As the space between vertebrae gets smaller, extra pressure can be placed on the discs causing tiny cracks or tears to appear in the anulus. If enough pressure is exerted, it's possible ... |
how does this .jpg file move like a .gif but when downloaded shows up as a .jpeg | It's lies.
The filetype isn't determined by the extension - not in this context anyway - it's determined by metadata in the file that says it's a gif.
My image reader on the desktop chokes trying to read it because it naively trusts file extensions, but the file utility shows clearly it's marked as a GIF in the metadata. | [
"A JPEG image consists of a sequence of \"segments\", each beginning with a \"marker\", each of which begins with a 0xFF byte, followed by a byte indicating what kind of marker it is. Some markers consist of just those two bytes; others are followed by two bytes (high then low), indicating the length of marker-spec... |
Can somebody build up a tolerance to electricity? | There is a difference between "not being in pain from x" and "being immune to x."
Pain tolerance is one thing, but a taser works by using electricity to create physical convulsions. This is direct stimulation of the muscles we're talking about. Adapting to THAT would require evolution to provide us with electrical insulation to sheath our skins/muscles/organs.
Just get a heavy jacket with metallic filaments in it attached to a capacitor. Put that electricity to USE. :-) | [
"To some degree, g-tolerance can be trainable, and there is also considerable variation in innate ability between individuals. In addition, some illnesses, particularly cardiovascular problems, reduce g-tolerance.\n",
"Zero tolerance policies violate principles of health and human services, and standards of the e... |
difference between nightmares and night terrors | The basics are that nightmares you wake up from and remember.
Night Terrors you don't wake up, can call out / yell in your sleep, yet you won't remember that particular dream ( although you can remember the feeling the dream gave you )
Source: Have had both Nightmares and Night Terrors consistently for years. I was explained this concept this simply the first time I asked. | [
"A night terror, also known as a sleep terror or \"pavor nocturnus\", is a parasomnia disorder that predominantly affects children, causing feelings of terror or dread. Night terrors should not be confused with nightmares, which are bad dreams that cause the feeling of horror or fear.\n",
"We have to distinguish ... |
how do we know that gravity curves spacetime and is not a force? | The theory which describes gravity as the curvature of spacetime (Einstein's general theory of relativity) makes a lot of predictions. And many of those predictions [have been verified](_URL_0_), which lends support to the theory. | [
"In general relativity, gravity can be regarded as not a force but a consequence of a curved spacetime geometry where the source of curvature is the stress–energy tensor (representing matter, for instance). Thus, for example, the path of a planet orbiting a star is the projection of a geodesic of the curved 4-D spa... |
How similar are modern day version of the Torah when compared to the oldest known versions? | Let me clarify a few terms: (1) by "Torah" I am going to assume you mean the entire Hebrew Bible/Old Testament rather than only the Pentateuch, (2) by "versions" I'm assuming you either mean "manuscripts" or a more esoteric scholarly concept of "the earliest attainable text" - I'll address both, and (3) I don't know which "modern day version of the Torah" you're referring to so I'm going to choose for you - the current NRSV translation of the Bible.
The question you have asked is, of course, subjective. It is hard to quantify degrees of similarity, and what would be "very similar" by one person's standard would be "very different" to others. I'll just lay out a bunch of data and let you decide.
What we have in terms of old manuscripts can be broken down into a variety of ways but I'll keep things simple. The current NRSV translation (and most others) of the Old Testament are based on the *Biblia Hebraica Stuttgardtensia,* (BHS for short) a scholarly reconstruction of the "earliest attainable text." The BHS uses as its base the Leningrad Codex from 1008 CE. The Leningrad Codex is the earliest complete Masoretic Text manuscript of the Old Testament. The Masoretic Text refers to a group of manuscripts produced by a group of Jews called the Masoretes. The masoretic tradition is important for its addition of vowel points to the otherwise only consonantal (abjad) Hebrew script, which provides clarity for numerous otherwise ambiguous readings, and for the reputation of the Masoretes for carefully preserving their text probably beginning in the 600s CE or so. As I mentioned, the Leningrad Codex serves as the base text to which various manuscripts, ancient translations, and textual reconstructions are compared in order to correct the Leningrad Codex to the “earliest attainable text.” Here is [the beginning of Genesis](_URL_0_) in the BHS. The main body text is an exact reproduction of what is in the Leningrad Codex while the bottom of the page contains the various different readings from ancient sources when they are different, among other things.
That brings us to ancient sources. You might be thinking to yourself, "wow, 1008 CE is really late for our earliest manuscripts." This is why the Dead Sea Scrolls were such a big deal! Dating from ca. 200 BCE - 70 CE, they effectively knocked back our earliest Hebrew manuscripts of the Old Testament/Hebrew Bible by 1,000 years when they were discovered in the 1940s. The Dead Sea Scrolls are 8-900 texts, many of which are books now in the Old Testament/Hebrew Bible, and are the earliest manuscripts we have of them in Hebrew.
I should also mention a couple other relevant means to get at readings more ancient than the Masoretic Text. (1) The Samaritan Pentateuch, preserved by the eponymous Samaritans in Israel, also represents an ancient independent text which scholars compare to the Masoretic Text. (2) Scholars also use ancient versions (that is, translations) of the Old Testament such as the various Greek translations often conflated as “The Septuagint,” ancient Syriac translations, and occasionally translations from Latin or texts quoted from early Church fathers, all of which can be compared to the Hebrew by back-translating or making speculations about the Hebrew text behind their translation.
So how close are the Dead Sea Scrolls and the other ancient translations and versions to the Masoretic Text? Well, it’s really a mixed bag. Two of the Dead Sea Scrolls which contain Isaiah will serve as a good comparison, 1QIsa^a and 1QIsa^b , the latter being the famous Isaiah Scroll; both found at the same site. The former matches the Masoretic Text practically word for word; the latter, however, contains about 1,000 textual variants from the Masoretic Text version, including entire verses missing or added at several points. Another interesting example is the book of Jeremiah. The Septuagint version, which scholars had long before the discovery of the Dead Sea Scrolls, was significantly shorter than the Masoretic Text, some 15%. It was presumed that the Hebrew was superior to the Greek in preserving a more original form, but when we found a manuscript of Jeremiah among the Dead Sea Scrolls (4QJer^b ), it matched the Septuagint version instead of the Masoretic Text version! This demonstrated that, in fact, the Greek version preserved by the Septuagint was more ancient than the one preserved in the Masoretic Text. There are numerous examples of such differences, and I would highly recommend Eugene Ulrich, “Our Sharper Focus on the Bible and Theology Thanks to the Dead Sea Scrolls” *Catholic Biblical Quarterly* Jan 2004, Vol. 66 Issue 1 for a superb summary of this and its implications for layfolk.
A question you didn’t ask but which I should propose anyway is, given the differences we can observe in the texts, can we reconstruct anything close to the original, or undo the changes later scribes made to the text? For the New Testament this is a much easier enterprise, but even with the Old Testament/Hebrew Bible the field of textual criticism has accomplished some amazing feats in reaching earlier forms of the text. The original versions are lost forever, there is little doubt about that, but I am continually impressed by the prodigious work in the field of textual criticism to dig further and further back.
Edit: clarification of some jargon. | [
"The oldest complete Torah scroll was discovered stored in an academic library in Bolonia, Italy by Professor Mauro Perani in 2013. It had been mislabeled in 1889 as dating from the 17th century, but Perani suspected it was actually older as it was written in an earlier Babylonian script. Two tests conducted by lab... |
what do doctors do with the empty space after a half brain removing surgery | The procedure is called a hemispherectomy (hemi = half, sphere, ectomy = removal) and they don't do anything with the empty space. It ends up filling up with cerebrospinal fluid. It's not like they are going to put a prosthetic brain in there for cosmetic purposes, haha. | [
"Another way a lobectomy can be performed is through a video assisted surgery. With this type the surgeon does not need to pry the two ribs open in order to get in. A few small incisions are made and surgical tools are inserted into the chest cavity. A small camera with a light will then be inserted. What the camer... |
the different types of pencils 2b,b,whatever else there is | Pencil leads come in a variety of hardnesses, obtained by altering the ratio of clay to graphite in the pencil. More clay makes the lead harder, but also means it makes a lighter mark. They are often used for engineering drawings because they produce a sharp, clean line without much variation in the darkness of the line.
Pencils with less clay are darker (blacker) & softer. They smudge easier, & can produce a range of darkness. They're often popular with artists because they can produce a variety of marks.
Pencils are often graded using the HB system in much of the world. B stands for Black, & H stands for Hard. The higher H numbers have more clay, & are lighter & harder, & the higher B numbers have less clay & are darker & softer. HB is a balance between the two. Sometimes you see F too, which is between HB & H, & is used for fine details in drawings. [Here's a diagram of the various shades.](_URL_0_)
American pencils use a number system, with #1 equal to B, #2 equal to HB, #3 equal to H, & #4 equal to 2H. The tests you hear about are filled out by colouring in bubbles corresponding to answers, & are marked by computers. The pencil used needs to be dark enough for the computer to be able to recognise which bubble was filled out, yet hard enough not to smudge outside the bubble & confuse the computer, so they use a pencil in the middle of the range. | [
"Dixon Ticonderoga makes a variety of pencils, including the Classic, Black, Noir, Tri-Conderoga, Microban, Laddie, My First (formerly Beginners), SenseMatic, and colored pencils. The pencils are available in different grades: #1 (Extra Soft), #2 (Soft), #2½ (Medium), #3 (Hard), and #4 (Extra Hard).\n",
"A mechan... |
LCD screens and Duck Hunt | As you already know, light guns need a CRT to work. Using a silicon (or any other covering) sadly wouldn't help at all.
When a CRT screen draws the image, it draws each pixel at a time - usually starting at the top, working left to right and then down a line until the whole screen is drawn. It then starts again. The whole time taken is called the 'refresh rate' and this is commonly done around 50 times a second*.
The light gun only 'sees' when a pixel is lit up on the screen that you're aiming at.
The time difference is calculated between you pulling the trigger. and the 'pixel' you're aiming at is lit up. The computer then calculates how long it has been since the screen was drawn and works out which pixel you were aiming at.
LCD/Plasma and other screens do still draw pixel-by-pixel, but the pixel is never completely off, so there is no single pixel that the light gun can see.
There's plenty of other alternatives, such as the infrared bulbs and camera that the Nintendo Wii has, but the old Zapper light guns need a CRT screen, sadly.
This is a slight simplification, but [Wikipedia](_URL_0_)'s is a bit weirdly worded but should fill in any further questions you might have.
| [
"\"Duck Hunt\" is a shooter game in which the objective is to shoot moving targets on the television screen in mid-flight. The game is played from a first-person perspective and requires the NES Zapper light gun, which the player aims and fires at the screen. It also requires a CRT television screen since the Zappe... |
How do you tell how long has a person been dead? | One way is by measuring body temperature. Given someone's weight and the temperature of their surroundings and their current temperature one can extrapolate how long the body has been cooling down from normal body temperature. Hopefully others can step in and explain other methods. | [
"In some cases, a person will be declared dead even without any remains or doctor's declaration. This is under one of two circumstances. First, if a person was known to be in mortal peril when last seen, they can often be declared dead shortly after. Examples would be the passengers of the \"Titanic\" that were not... |
What's the difference between Deep Blue's algorithm and Monte Carlo Tree Search? | The difference is in how they decide which move to take.
Deep Blue has a function to tell how good the board is for him. He uses this function to decide which move to take.
On the other hand, for some games no well working function to rate a board is known (like go). For such one uses the MCTS. Each legal play is done and then the game is finished n-times with both sides taking random moves. The play that has the highest number of wins will be taken.
So, Monte Carlo Tree Search is purly "random" while Deep Blue depends on a rating function. | [
"In computer science, Monte Carlo tree search (MCTS) is a heuristic search algorithm for some kinds of decision processes, most notably those employed in game play. MCTS was introduced in 2006 for computer Go. It has been used in other board games like chess and shogi, games with incomplete information such as brid... |
given the fragmented instant messaging market and the failure to create a standard protocol, why aren't there email clients that make using email more like instant messaging? | Huh?
Email essentially already is instant messaging, if the user utilizes it in that way. You can get notifications that pop up on your computer that tell you that you just got an email, and it's essentially instance. Your phone can tell you that you just got an email, and it's essentially instant.
I sometimes use email like that with my less Tech Savvy family members. I will have a 10 or 20 email long chain in only a few minutes, because we are just emailing back one or two sentences to each other.
Today, I don't think there is an issue with email clients or technology. It's simply how the users utilize it.
Also, instant messaging it's probably not as popular as it once was, since the Advent and popularity of phones and texting has taken over from that. | [
"Empirical studies demonstrated that all team members on a software development team used this tool effectively. Unlike instant messaging, email messages are intended to be more stand-alone and less sensitive to the context of communication, and thus producing email messages requires more time than traditional IM m... |
Zebras in the middle east? | There are some zebra-like fossils known from Asia, but it's obviously hard to know if they had stripes! | [
"The plains zebra's range stops short of the Sahara from South Sudan and southern Ethiopia extending south along eastern Africa, as far as Zambia, Mozambique, and Malawi, before spreading into most southern African countries. They may have lived in Algeria in the Neolithic era. Plains zebras generally live in treel... |
Is it better for a computer to never turn it off, or to turn it off regularly? | The TL;DR on all of the responses is essentially "If you build a System correctly, it doesn't matter whether you leave it on or off, it will outlive its usefulness long before it stops working".
| [
"Modern interactive computers require that the computer constantly be monitoring for user input or device activity, so at some fundamental level there is an infinite processing [[idle loop]] that must continue until the device is turned off or reset. In the [[Apollo Guidance Computer]], for example, this outer loop... |
why are saltwater aquariums so hard to maintain, but the fish can live in the ocean with a lot more variables? | It's largely *because* there are so many variables that are typically present in the ocean, but not in an aquarium. There are a million different chemicals that are present in the ocean in specific concentrations that won't be present in the aquarium, often because we don't know which of them is important or not. Even when they're not directly related to fish health, simply *changing* that environment is stressful. Reefs, mostly, don't change. They haven't changed significantly in tens of thousands of years\*. Because of that, marine life isn't accustomed to dealing with changes.
They're also part of hugely complex web of resources - every fish on the reef has a specialized diet. You can replicate that diet, but only to a degree. For instance, most marine angels eat corals, which is undesirable in an aquarium because corals are *expensive*. On the reef, the angel could graze from place to place, eating a few polyps on a colony of thousands and move onto another colony while the first recovers - in an aquarium, there's only so many corals to munch on so they're all going to get munched on all the time. Ok, so don't keep angels with corals. Except that some angels are obligate corallivores - their diet *must* include coral. Tangs, like [blue regal tangs](_URL_1_), eat algae, specifically macroalgae (seaweed), which means you *have* to include seaweed in their diet. Except your angels, even if they don't need coral, still want meaty foods. So you have to feed two different things. Puffer fish have a fused tooth like a beak, which they use to scrape meat out of shells - they eat clams and snails. If their diet does not include clams and snails, their beak doesn't get worn down and, just like a rabbit, it will continue to grow until it hurts them. Every single fish in your aquarium will have a specialized diet, and often we don't know what all is in that diet. Not to mention the rest of the food web, from phytoplankton, zooplankton, diatoms, copepods, amphipods... Some foods may not be available in your tank without feeding *those*, and so on.
All of that assumes your fish will eat prepared foods *at all*. Except for *basically* most clownfish, seahorses, and a very, *very* small group of other fish, literally every other saltwater fish you see in an aquarium was wild caught. All of them. You may be offering them a high quality food pellet with every nutrient they need to survive, but they may never recognize that as food. It doesn't *look* like food to them, because even if it's made of shrimp and seaweed, it doesn't look like shrimp and seaweed. Some saltwater fish are very picky eaters and will never take to prepared foods, like [seahorses](_URL_0_) (that's my tank!). They will *only* eat live food, or frozen food like thawed mysis shrimp, even if they're captive bred!
The ocean is also big enough to absorb problems. Consider the [nitrogen cycle](_URL_3_): fish produce ammonia during their metabolic processes, which is broken down by bacteria, then broken down again until it becomes nitrate. In nature, that nitrate is absorbed by plants for the nitrogren, converted back, eat by the fish, converted into ammonia...etc. In your aquarium, you are always adding nitrogen via the food, but it's not *going* anywhere. Once it enters your tank, it stays there until you remove it. In the ocean, that's millions of gallons of water to absorb and spread out the nitrate while the plants absorb it, plus there's tons of plankton also absorbing it, *plus* there's tons of surface area for the nitrogen to evaporate into the air. None of that exists for your aquarium, so nitrate can build up very quickly. The same applies to things that mess with your pH (which has to be very consistent at 8.3 to 8.4) - the pH of the ocean doesn't change\*, it's too big, but your teeny tiny tank may see pretty big swings in pH, or salinity, or temperature, which the fish are not equipped to deal with. There are so many factors to keep track of in your aquarium and not a whole lot of time to do it before it's changed enough to be stressful for the fish.
There's also the problem of space: even small reef fish that pick one hole and live there, or one small territory are used to a *lot* of space around them. Nomadic fish like tangs are used to having huge amounts of room to swim through. Being stuck in a small tank can be very stressful, especially if you make the mistake of overcrowding your tank or not having an appropriately sized tank (adult tangs need tanks in the hundreds of gallons to feel comfortable). Along with space, they're used to having features to hide in or hide around, and having big open spaces with no rocks or corals can make them feel unsafe. *They* don't know there aren't any sharks around, so they're looking for a place to hide, just in case, and there aren't any. Which often leaves you with a catch 22: less rock so your fish have more room to swim, but no place to hide, or places to hide but no room to swim. Finding that balance can be difficult.
There's more I could go into, like compatibility (which fish will eat each other or fight each other), how stressful transportation is, some of the questionable methods used to catch aquarium fish (like using cyanide - yes it's exactly as dangerous as it sounds, for both the fish and the diver), the deplorable conditions some of them are kept in before they make it to your tank...some of the absolutely, hideously deplorable conditions people try to keep them in at home...believe it or not, even saltwater fish are hardier than people give them credit for, you just would not believe how many people do it *wrong*, and how pants-on-head stupidly wrong they do it ("I just set my 10g up yesterday, the ammonia is reading at 4ppm, the pH is at 7.2, and the salinity is at 1.030...can I get three blue tangs, four clownfish, two angelfish, eight damsels, an eel, and a puffer? Thanks..."). (Seriously, if you want to set up an aquarium, fresh or salt, awesome! Go to /r/Aquariums and ask questions, or just PM me, aquariums are literally my job; I'm more than happy to help! Do your research, do it right, be patient, and take care of the animals you're bringing into your home.)
*Global climate change is having an effect: see [ocean acidification](_URL_4_). Along with rising temperatures and changes to salinity, the effects are [not good](_URL_2_). Marine life is having a really tough time dealing with the changes going on in their environments for many of the same reasons they have trouble dealing with aquariums. Their ecosystems have evolved a very delicate balance, and they all fit very carefully inside that balance, so when one thing gets out of whack the whole reef suffers. | [
"Home aquaria and inland commercial aquariums are a form of RAS where the water quality is very carefully controlled and the stocking density of fish is relatively low. In these systems the goal is to display the fish rather than producing food. However, biofilters and other forms of water treatment are still used ... |
what is an elementary function? | The elementary functions are a set of well known functions such as powers of x, roots of x, exponentials, trigonometric functions and their inverses, and most importantly any combinations of them, for example e^sinx + x^(2).
Non elementary functions are those that can't be written like that. For example if I define the function:
f(x) = 1 if x is rational and f(x) = 0 otherwise
Then f is a non elementary function. This function has a specific name - Dirichlet function - but most non elementary functions don't have a name or an easy way to describe them. | [
"In mathematics, an elementary function is a function of one variable which is the composition of a finite number of arithmetic operations , exponentials, logarithms, constants, trigonometric functions, and solutions of algebraic equations (a generalization of \"n\"th roots).\n",
"Elementary Functions- a study of... |
if temperature affects air pressure, would the temperature on a planet with a thinner atmosphere feel different than the same temperature on a planet with a thicker atmosphere? | How temperature feels is subjective because it is a feeling. Factors such as humidity may impact how temperature feels but humidity is related to much more than how thick the atmosphere is and its quite localized. | [
"In the field of planetary atmospheres, David Catling and Tyler Robinson have proposed a general explanation for a curious observation: the minimum air temperature between the troposphere (the lowest atmospheric layer where temperature declines with altitude) and stratosphere (where temperature increases with altit... |
where does water pressure come from? | I'll just try to elaborate a bit. There are only 2 common ways to increase the pressure of any fluid (including water). Pressure is equal to the density of the liquid times the height, it doesn't matter how wide or deep the pipe is, the water pressure at the bottom of a 2 inch diameter tube that's 100 feet tall will be the same as a 2000 inch diameter tube that is 100 feet tall. So water is either collected at high elevation (rain collecting) or pumped to a higher elevation (tank at the top of a tower). Pumping is the second method to increase pressure, which is pretty obvious, using electrical power, to turn mechanical parts that apply force to the fluid to increase pressure. | [
"The perception of water pressure is actually the speed of the water as it hits a surface, (the hands, in the case of hand washing). When an aerator is added to the faucet (or fluid stream), there is a region of high pressure created behind the aerator. Because of the higher pressure behind the aerator and the low ... |
why does an emergency door have a grill / bars inside its window? | > I'm almost certain that every emergency door have a window and a grill in it.
Many do not, but it is a common feature in such doors to allow some vision of what is past them. You can avoid walking into a fire or smoke hazard with such a feature.
> Why does it have those? It doesn't mean like the grill will make the door stronger, right?
The grid of wire does not make the door stronger. It does however make the *window* stronger. Wire mesh can keep even shattered glass mostly in place, and keep both debris and intruders from passing through. | [
"The U.S. State Department often uses steel grillwork much like a jail to seal off parts of a home used by U.S. Foreign Service members overseas when they are living in cities with a high crime threat. In some cities, the entire upstairs area is grilled off, as well as every window and door to the home. Other homes... |
- the recent hate on nbc | From the sounds of it, their coverage has been somewhat uneven, between cuts, camerawork and adverts.
However it seems the most notable culmination that has got people riled is the replacement a tribute to victims of a terrorist incident in the UK on the 7th of July in 2005 that took place during the opening ceremony. As the replacement was seen as somewhat trivial in comparison (an interview with Michael Phelps by Ryan Seacrest, if what I'm hearing is correct?), some people are disappointed and offended at NBC's broadcast choices.
For a contextual comparison, some choose to parallel it with the outcry that might follow a national broadcaster sidelining a 9/11 tribute to cover something trivial instead. | [
"General manager Mike Pumo refused to elaborate on the decision, other than the show's content did not \"raise the red flag\" during pre-screening. Stratton Pollitzer, deputy director of Equality Florida, considered the show hate speech, saying, \"I think this program is a piece of homophobic propaganda and it has ... |
Why can't people with O-Negative blood donate platelets? | O- is in short supply due to the demand as universal donor.
B- is just an insanely rare blood type, less than 1% in caucasians if I remember right. Important because the only 2 types this type can receive (without risking sensitization to D) is b neg and o neg.
Theres no reason they couldnt donate platelets, but since platelet type is mostly a non issue these days it's much more useful to donate red blood cells. However, platelets are also in demand because of their short date, so I hadn't realized they were refusing those platelet donations though | [
"Platelets are the clotting cells of the blood, and when donated, frequently go to cancer patients, because due to chemotherapy many cancer patients are unable to generate enough platelets of their own.\n",
"Problems with apheresis include the expense of the equipment used for collection. Whole blood platelets al... |
If you can't hear thunder (but can see distant bolts of lightning) are you still in danger? | The odds of getting hit by lightning are pretty low no matter the conditions, but if you're super scared of things, it is very remotely possible to be struck by a [bolt from the blue](_URL_0_) 15 or 20 miles from a thunderhead.
I've been a lightning watcher all my life (56 y) and so was my dad. Neither of us ever even got close to being struck by it. | [
"The U.S. National Lightning Safety Institute advises American citizens to have a plan for their safety when a thunderstorm occurs and to commence it as soon as the first lightning is seen or thunder heard. This is important as lightning can strike without rain actually falling. If thunder can be heard at all, then... |
Why did some areas of Africa quickly convert to Islam, some convert slowly to Christianity, and others keep worshipping tribal gods? | The answer is that they didn't convert all that quickly at all. Those areas that did convert to Islam did so quite gradually. Much of Northern Africa, as former Roman provinces, were Christian during the Arab conquests, but gradually became more Muslim over time, often thanks in part to economic pressures. Similarly, non-Roman city states in East Africa with deep connections to Muslim areas through trade over the Indian Ocean gradually converted to Islam over centuries. It's no mere accident of history that Islam's spread mirrors trade routes: it was easier to find trust and economic security between trading partners when they shared a religion.
However, you are mistaken in saying that Christianity has been slow to spread in Africa. There are hundreds of millions of African Christians thanks to heavy-handed and concerted evangelism efforts. Native religions are much less common. Of course, as with Europe, native beliefs are often incorporated into the way they practice Christianity. Typically, Christianity is more prevalent in areas that never developed strong Muslim communities and received heavy evangelism efforts, while Islam is found spread out along ancient trade routes. This isn't to discount communities like the Christians in Egypt, who have been there since Roman times. | [
"Islam came to North Africa at a moment when there was nothing of a calibre sufficient to oppose it, while there were many native elements favourable to its advance. The Romans were largely obliterated except in Berenice and the rest of the small area under Byzantine rule. Civilisation in Berenice was almost extinc... |
what happens to the human body when it experiences spontaneous decompression? does it just pop? | "Coward, Lucas and Bergersen were exposed to the effects of explosive decompression and died in the positions indicated by the diagram. Subsequent investigation by forensic pathologists determined Hellevik, being exposed to the highest pressure gradient, violently exploded due to the rapid and massive expansion of internal gases. **All of his thoracic and abdominal organs, and even his thoracic spine, were ejected, as were all of his limbs.** Simultaneously, his remains were expelled through the narrow trunk opening left by the jammed chamber door, less than 60 centimetres (24 in) in diameter. Fragments of his body were found scattered about the rig. One part was even found lying on the rig's derrick, 10 metres (30 ft) directly above the chambers. The deaths of all four divers were most likely instantaneous."
[Byford Dolphin Accident](_URL_0_)
There is a picture of what was left of one of the divers, but I couldn't find it. Essentially, if you read the above, what was left on the stretcher didn't amount to much,
Edit: This was an extreme situation obviously. | [
"The term \"decompression\" derives from the reduction in ambient pressure experienced by the organism and refers to both the reduction in pressure and the process of allowing dissolved inert gases to be eliminated from the tissues during and after this reduction in pressure. The uptake of gas by the tissues is in ... |
Why can't I cleanly wipe the condensation off my bathroom mirror after a shower? | Condensation is caused by the relatively cool surface of the mirror pulling moisture out of the air. The water vapor in the air essentially loses energy, that is, cools off and phase changes into water, when it encounters this surface.
When you wipe it, you get rid of the droplets that have formed on the surface of the mirror. What you haven't addressed is whats causing it in the first place - the cool mirror. So a new layer of droplets quickly forms. If you take a hairdryer on hot and blast the mirror THEN wipe it, it will no longer form condensation. This is known as the female solution. You can also spit on the mirror and wipe it around. The body temperature phlegm should slow/stop the condensation. This is known as the male solution.
Some fancy hotels actually have mirror heaters to avoid this problem altogether. | [
"The simplest version of a mirror coating is a single layer of a deposited thin film of a suitable metal, usually prepared by ion beam deposition, sputter deposition or vapor deposition. However, this kind of coating is very prone to scratching, and degrades, especially in a corrosive environment like salt water.\n... |
During timeperiods with more oxygen in the atmosphere, did fires burn faster/hotter? | Yes. And during periods with lower oxygen levels, fires burned more slowly or not at all. Some natural fuels will burn at high oxygen concentrations but not low. [This article](_URL_0_) examines these relationships. Wildfires may actually act to stabilize atmospheric oxygen levels. If the concentration increases, fires will burn faster and consume the excess. If the concentration decreases, fires slow down and consume less oxygen, allowing the concentration to rise again. Check out [this excellent paper(PDF)](_URL_1_) to learn more about this and other relationships between fire and climate, ecology, evolution, etc. | [
"It is not necessary but highly likely that this kindling phase took place in an oxidising atmosphere: an oxygen-rich fire is likely in any case, since it is much more effective in producing heat. Further, the fact that reducing fires are extremely smoky would probably have been considered as undesirable, and was t... |
How accurate is the information that Leif Erickson actually discovered North America? | Hi, not discouraging others from answering here, but you may be interested in a few earlier posts
* /u/400-Rabbits in [Did Vikings ever make contact with North America before Christopher Columbus?](_URL_2_)
* /u/textandtrowel in [What do we know about Vinland?](_URL_3_)
* /u/A_Crazy_Canadian in [What information about Leif Ericsson can be verified as historically accurate?](_URL_4_)
For reference, L'Anse aux Meadows is a [Canadian National Historic Site](_URL_0_) and [Unesco World Heritage Site](_URL_1_) | [
"After quitting Hanover Beamish devoted much attention to Norse antiquities, and in 1841 published a summary of the researches of Professor Carl Christian Rafn, relative to the discovery of America by the Northmen in the tenth century. Although the fact had been notified as early as 1828 (in a letter in Niles' Regi... |
why fat forms where it does | I'm sorry if the answer is incorrect but my lecturer told me that it has to do with gender.
Male: The stomach.
Female: Buttocks. | [
"Adipose tissue, commonly known as fat, is a depository for energy in order to conserve metabolic homeostasis. As the body takes in energy in the form of glucose, some is expended, and the rest is stored as glycogen primarily in the liver, muscle cells, or fat.\n",
"Fat body (\"Corpus adiposum\") is a loosely org... |
When (and why) did capital punishment start being carried out by lethal injection? | The history of lethal injection is an interesting and *horrible* one. Lethal injection was first suggested as a procedure in 1888, by an American doctor, incidentally a year after the abolition of capital punishment in Maine. In some ways, lethal injection has always been a very American thing. At the time, victims were executed through hanging- and hanging is not nice. Whether it involves horrible damage to the neck and asphyxiation, whether it's public or private, hanging is frankly gruesome as hell. And although some society didn't mind- or even supported- that aspect of it, a subset certainly did, and tried to find less gruesome, more 'humane' methods, or at least more humane in their eyes, such as electrocution or, indeed, lethal injection.
However, for a variety of reasons, this never went far. Lethal injection is and was expensive- especially compared to hanging. It was not necessarily less gruesome. It leant a more medical air to execution than some people would have liked. It was more personal, as someone would have been actively injecting the victim, which didn't allow the distance and removal from the death that hanging did, even for the hangman. It was an unattractive option for accountants and executioners alike.
But the medical air of lethal injection certainly appealed to some people. Nazi Germany dabbled with lethal injection as well. It was used in the murder of the severely disabled, including young children and babies, where the victims would be injected with a number of toxic substances, such as phenol. Originally this eugenics program killed infants, before expanding to include older children, teenagers and eventually adults. Parents at first did not understand what was going on- sending severely disabled children to institutions and asylums was the norm for Germany at the time, as parents often didn't have the ability or facilities to safely care for their children, and some also sent their children to asylums out of shame or embarrassment. They were told their children had died of natural diseases- influenza, pneumonia, heart conditions- and that was that. Eventually, some parents and communities realised what was happening, so many children dying, and began to refuse to send their children to institutions. But there was enormous pressure to do so, put on by the Nazi government, with parents threatened with their children being removed from their care, or the father being sent to the Eastern front, which was almost a death sentence at some points in the war.
From 1939, Aktion T4, which was the planned, systematic murder of the mentally, intellectually and developmentally disabled, was expanded to adults, first those found in the Polish institutions being overrun by the SS, and then across Germany. The majority were shot or gassed, not killed through lethal injection as the children were.
Why was lethal injection the chosen method of murder, for children in particular? Lethal injection carried a reputation of being painless (it wasn't) and it made the procedure medical. A doctor, a paediatrician, who had spent his life working with and saving children, might have found it difficult to allow a child to be shot in the head. But it might have rested easier on their consciences if a child died from a Luminol overdose. It would have seemed less like killing, more like euthanasia, being medicalised, sanitary and 'civilised'. Indeed, for these reasons, lethal injection appealed to a number of people, not just in Germany or America, but also in the UK.
In the late 1940s, the British Royal Commission on Capital Punishment was considering the use of the lethal injection- it not having yet been used. The British Medical Association rejected the suggestion, on the grounds that it was cruel and certainly painful, but also because associating anything medical with death was going to be a big PR mistake. The BME did not want that medical air to be added to capital punishment, and the doctors who would administer the dosage would not have been keen- actively ending lives goes against most people's morals, and even if they support capital punishment, lethal injection confronts the executioner with the reality of the act in a way that hanging, gassing or firing squad doesn't allow, although more modern methods, through lethal injection machines, have removed this problem.
Lethal injection was only actually used in a democratic country, openly and legally (eg not Nazi Germany) in 1982, but was first suggested in 1977, a year after capital punishment was once more resumed in the US, and the same year an execution was actually carried out for the first time since the resumption, that of Gary Gilmore, executed by firing squad, in Utah, and ten years after the previous execution in America, in 1967, that of Luis Monge by gassing. In 1972, the use of capital punishment was ruled to be unconstitutional, due to it being considered a cruel and unusual punishment, and although it was reinstated in 1976, there was certainly a need for a method of execution which would *not* be seen as cruel or unusual, and lethal injection- passing away peacefully and painlessly whilst unconscious- was ideal.
The state medical examiner of Oklahoma, one Jay Chapman, who was also a doctor, suggested lethal injection as a form of execution, believing it would be less painful. His plans were approved by a leading anaesthesiologist, also of Oklahoma, named Stanley Deutsch, and the form of lethal injection was to involve a fast acting barbiturate and induced chemical paralysis. It was soon adopted into the Oklahoma state criminal system, and the supposed relative painlessness and the medicalised, scientific form of execution apparently appealed both to the general public- who could see themselves as supporting a clean, humane procedure, compared to a brutal, violent one such as hanging, electrocution or the gas chamber, which was used in American history, which could be associated with the Holocaust as well as having a reputation for causing suffering- as well as other state governments, being quickly adopted across the US. | [
"The methods for execution at San Quentin have changed over time. Prior to 1893, the counties executed convicts. Between 1893 and 1937, 215 people were executed at San Quentin by hanging, after which 196 prisoners died in the gas chamber. In 1995, the use of gas for execution was ruled \"cruel and unusual punishmen... |
What are the differences in the metabolisms of someone who can't get fat and someone who gains weight easily? | While this doesn't quite answer your question, perhaps it will give you some information that is part of the answer.
Human microbiota (all the microbes in and on you) work has exploded in the last 10 years. One huge piece of research to come out of this is that [lean people and obese](_URL_0_) people harbor different profiles of bacteria (and different bacterial genes) in their gut. They took identical and non-identical twins, and their mothers, compared who was lean or obese, what microbes they had in their gut, and what the gene content of those microbes was. The idea of looking at twins is then you can control for the gene content of the host. What they found in short is that obese people had less diversity of bacteria (and their genes) in their gut along with a different assortment of bacteria. Some thoughts for why this might be is that the obese profile helps the host get more energy from their food.
However, at this point, it's kind of a chicken/egg discussion. We know what an obese microbiota looks like. Do people get inoculated with an obese microbiota and then become obese because of it? This could explain why we see obesity in families. Or is there something that individuals do that shift their microbiota towards that of an obese one, and it "helps" them become obese?
I'm going to speculate now based on what I've read, and the people I've talked to about this (I've actually met and had a conversation with the lead author on that paper I linked to). I think this all might actually be a combination of things. Perhaps mom eats in a way that not only encourages weight gain, but also encourages an obese microbiota. She gets stuck in a cycle where her microbiota requires more food, so she eats more, maintaining her obesity. She then inoculates her kids with that profile, while maintaining the necessary external things that support their obese profile and that keeps them obese. And you can look at it from the flip side, lean people doing the things that maintain a lean profile AND inoculating their kids with it AND teaching them the habits that maintain that leanness. I have to wonder if part of the difficulty for some in losing weight isn't totally that it's "hard" to lose weight, but that it's hard to shift your microbiota back to that of a lean person. | [
"All body shapes are different, meaning, people carry fat in different places. Some locations on the body are more metabolically active than others, and those areas will lose weight quicker than those that are not as metabolically active. For many people, abdominal fat is more metabolically active, and can be reduc... |
how does a build up of lactic acid in an athlete's muscles cause them to sometimes thow up | Throwing up is one of a few things the body just defaults to when it senses something is geberally wrong. Better safe than sorry, maybe it's something you ate, let's throw up just to be sure. Makes sense from an evolutionary stand point.
Also, when so much lactic acid is built up, it'll sometimes end up in your actual stomach. This will irritate the stomach and throwing up gets rid of it. | [
"The presence of lactic acid has an inhibitory effect on ATP generation within the muscle; though not producing fatigue, it can inhibit or even stop performance if the intracellular concentration becomes too high. However, long-term training causes neovascularization within the muscle, increasing the ability to mov... |
is paying off a mortgage like paying rent? | ...Sort of? It is a regular bill which needs to be paid so it seems similar. However a major difference is that the money paid into the mortgage isn't really gone in the same way as rent. You are gaining equity or ownership of the property so when it is sold you get that money back. You can even sell before the mortgage is done and pocket the difference between the mortgage and sale price. | [
"Some mortgage companies also charge early payment penalties if the homeowner pays more than is due in order to reduce the interest owed and to shorten the remaining term of the loan. The fees typically negate this advantage at least in part.\n",
"The mortgage part was typically on an interest only basis, while t... |
why are veterans held in such high regard in america and why do some veterans walk around in uniform when not on duty? | Because they fought for our country. They risked their lives for us. I think they deserve a little damn respect. | [
"Because of intense group solidarity and unique daily hardships brought by combat, many veterans feel alienated from citizens, family, and friends when they return. They often feel they have little in common with civilian peers; issues that concern friends and family seem trivial after combat. There is a clarity of... |
How did kingdoms with two simultaneous kings come about and how did it work? | On your tangent: "state" is just a generic (and somewhat ill-defined) word for a sovereign political entity, it doesn't imply anything about the form of government. Kingdoms are states. | [
"For years both kingdoms were involved in wars until the kingdom of Tallo was defeated. During the reign of King of Gowa X, \"I Manriwagau Daeng Bonto Karaeng Lakiung Tunipalangga Ulaweng\" (1512-1546), the two kingdoms were reunified to become twin kingdoms under a deal called \"Rua Kareng se're ata\" (\"dual king... |
Could a planet theoretically exist which is much larger than earth but made of less dense materials and therefore still have earth gravity? | The important thing to remember is that the force of gravity from an object is dependent mainly on two things; the mass of that object, and your distance from its center of gravity.
So, laying aside your requirement for solid ground for now, the simple answer is yes. We just have to have our hypothetical planet fulfill the following equation:
-9.8m/s^2 (which is the acceleration due to gravity on the surface of the Earth) = -(M (the mass of the hypothetical planet) * G (the Gravitational Constant, or 6.674 x 10^-11 (m/kg)^2 ) / r^2
This simplifies to...
9.8 = 0.00000000006674M / r^2
or
M / r^2 = 146838477674.6
What this equation basically says is that, for a planet to have Earth gravity on the surface, its mass in kilograms must be around 150 billion times the square of its radius in meters.
So, say you wanted a private planet that had Earth gravity. Let's say you wanted the radius to be about 1km- or 1,000m. Let's plug that into the equation:
M / ( 1000^2 ) = 146,838,477,674.6kg
M / 1,000,000 = 146,838,477,674.6kg
M = 146,838,477,674,600kg
So, for our private planet to sustain 1G at the surface, it'd need to have a mass of 146 trillion kg. Let's see how easy that is to attain.
We know that the planet has a radius of 1000m, so we can use that to figure out the planet's rough volume, using the equation for the volume of a sphere, which is:
v = 4/3 * pi * r^3
The end result of that equation is a volume of about 4.189 billion cubic meters.
We can then take that volume, and plug in the mass we already figured out to find out how dense our microplanet needs to be.
Density = mass / volume
Density in this case = 1.468 x 10^14 kg / 4.189 x 10^9 m^3.
Density = 35,044 kg / m^3
That's *really dense*. To make it easier to calculate, we'll reduce it down into the simpler form of grams per cubic centimeter.
At 1,000,000 cubic centimeters per cubic meter, and 1,000 grams per kilogram, the density of our microplanet reduces down to a bit more than 35 grams per cubic centimeter. That's nearly twice as dense as solid gold. We don't even know of an element that can be that dense. The highest our charts go is around 22g/cm^3 .
Let's be a bit more reasonable. Let's say we want a planet the size of the Moon that has Earth gravity on the surface.
The Moon has a radius of about 1737km, or 1737000m, so let's plug that into our equation:
M / ( 1737000^2 ) = 146,838,477,674.6kg
M / 3,017,169,000,000 = 146,838,477,674.6kg
M = 443,036,502,846,995,207,400,000kg
That's over 443 thousand billion billion kilograms, but we'll just write it out as 4.43 x 10^23 kg.
We also need to figure out the volume of the Moon. It ends up being about 2.195 x 10^19 m^3 .
Plug those together, and you get an overall density of 20.18g/cm^3 . still ridiculously high, but we know there are elements that exist that can give us that level of density.
Now, earlier, you asked what the largest solid planet could be. For this, we'll need to rewrite our original equation, and put it in terms of one variable (the radius), and use a defined density. We'll go with diamond, because it's a very light, very durable solid, weighing in at just 3.515g/cm^3 .
Here's our original equation:
M / r^2 = 146838477674.6
Now, we need to bring it all in terms of the radius, r. To do this, we can express the mass as a function of the planet's volume and density.
M = 4/3 * pi * r^3 * density
Refactoring diamond's density, it ends up being 3515 kg/m^3, so we can go ahead and plug that, along with the 4/3 and pi, into the equation.
M = 14723.6 * r^3
So, we now have M in terms of r, so we can slot that value back into the equation:
14723.6r^3 / r^2 = 146838477674.6
We can factor out the r^2 from the denominator right off, because we have the r^3 in the numerator. That leaves us with this:
14723.6r = 146838477674.6
Then, we divide:
r = 9,973,001m
So, our hypothetical diamond planet has a radius of 9,973km- a bit more than half again as great as Earth's.
Now, suppose that we're willing to give up a solid surface, and just have an ocean planet, made entirely of water. Do the math, and we have a planet that's got a radius of 35,000km.
You can also figure it out for more exotic materials, like aerogels, but I'm not going to go into that here. | [
"Recent discoveries have uncovered planets that are thought to be similar in size or mass to Earth. \"Earth-sized\" ranges are typically defined by mass. The lower range used in many definitions of the super-Earth class is 1.9 Earth masses; likewise, sub-Earths range up to the size of Venus (~0.815 Earth masses). A... |
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