question stringlengths 3 301 | answer stringlengths 9 26.1k | context list |
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when people go to the beach... men are shirtless with shorts (sometimes speedos 😳) and women are wearing a two piece (sometimes topless 😈) why is it that we freak out when people see us in our underwear, and we are perfectly fine when people see us in our “beach underwear” ? 🤔 | Context is important. I'm not surprised to see a hot dog at a hot dog stand. I'd be surprised if I opened my wallet to pay for a hot dog and it only had a hot dog inside.
I'm not surprised to see beach clothing at a beach, but would be concerned if I'm about to go into surgery and the surgeon shows up in a speedo. | [
"Underwear is sometimes partly exposed for fashion reasons or to titillate. A woman may, for instance, allow the top of her brassiere to be visible from under her collar, or wear a see-through blouse over it. Some men wear T-shirts underneath partly or fully unbuttoned shirts. A common style among young men (2018) ... |
what happens when you get new glasses? | Pretty much, yeah. Your brain can adapt pretty fast. An experiment with upside down glasses revealed that it takes a few weeks for the brain to adjust. The person's brain literally adapted to it, and his vision flipped itself rightside up.
Your brain just got used to a slightly blurred vision and adjusted accordingly. Now you give it super sharp vision, which is kinda like seeing everything slightly magnified. You'll adjust fairly quickly. | [
"The glasses appear to be more susceptible to damage than the screwdriver; in \"The Girl Who Died\", a Viking warrior takes the glasses off the Doctor's face and easily breaks them in half. Nevertheless, the glasses continue to appear via replacement or repair until the end of the season. They return the following ... |
why is it that when you're in a plane and the plane is turning sideways, your hair doesn't also gravitate towards the actual ground of earth but keeps gravitating towards the floor of the airplane? | Same reason water stays in a bucket when you swing it over your head. Centrifugal force. | [
"Another problem in this maneuver is that higher lift from the faster moving outside wing will roll the airplane to the left (or to the right). Most pilots find holding forward right (or left) stick necessary throughout the pivot.\n",
"no rotational acceleration (a turn). If you turn either your aircraft or your ... |
how does nicotine affect a body's dopamine level? | There's really a ton of misinformation about this.
People will tell you that nicotine releases dopamine because it's pleasurable, or it's pleasurable because it releases dopamine, but neither of those is very accurate at all.
First off, there is no such thing as your "dopamine level". Neurotransmitters are not like hormones. Hormones get released into your body's general circulation, and if there's more testosterone (for example) in your system, then testosterone receptors throughout your body will get stimulated more.
But with neurotransmitters, one group of neurons can be using neurotransmitter X to send a particular message to some other group of neurons, and a different group of neurons (even in the same area) could be using the same neurotransmitter to communicate with some other group of neurons about something completely different.
As for nicotine:
Nicotine blocks nicotinic acetylcholine receptors (acetylcholine is a neurotransmitter, and nicotinic ACh receptors are a subtype of that receptor, which is also present in most of your muscles).
ONE of the systems in your brain that uses dopamine, the mesolimbic system, is related to motivation / goal directed behavior (this is often misrepresented as being a "reward system" but that's quite wrong). This is often called a dopaminergic system, but that is still misleading, because only a small part of the system is dopaminergic. As with most neural circuits, it's composed of many different groups of neurons that send signals to each other using various neurotransmitters, including glutamate, GABA, dopamine, acetylcholine, and others.
Some parts of the system have nicotinic acetylcholine receptors, and nicotine affects these.
ELI5:
There are systems in your brain that help govern goal directed behavior. A small part of one of these systems is dopaminergic, but most of it uses other neurotransmitters, including acetylcholine. Nicotine blocks acetylcholine receptors, changing the behavior of the system. | [
"Nicotine activates nicotinic receptors (particularly α4β2 nicotinic receptors) on neurons that innervate the ventral tegmental area and within the mesolimbic pathway where it appears to cause the release of dopamine. This nicotine-induced dopamine release occurs at least partially through activation of the choline... |
how are blind people taught to understand the world? how much do they truly understand about their shape and the shape of other things? | Blind people simply can’t see. They will never understand colour, or what it means for things to look beautiful, but they still have their other senses.
Don’t underestimate how good sound is for building up an understanding of the space you are standing in. Blind people can also touch things and easily understand their shape. Without vision you can build up a pretty good idea of the world around you. If you were born blind then you will have learnt naturally how to utilise your other senses to understand the world and would not need to be taught by someone else how to understand it.
Most people who are considered legally blind are not fully blind, they can see to some extent. Of course this is not true for all blind people, but the majority of blind people have some vision. | [
"A sighted child who is reading at a basic level should be able to understand common words and answer simple questions about the information presented. They should also have enough fluency to get through the material in a timely manner. Over the course of a child's education, these foundations are built on to teach... |
If a duke in medieval England, France, or Germany wanted his second son to inherit his lands and titles, would he have any way of disinheriting his oldest son? | In England, it would depend on a couple of things.
If the real property were held in fee tail (Entailed) a person would need the agreement of the heir to break the fee tail.
If a tail could not be broken, the ancestor/father could leave all of his personal property,money or unentailed real property any way that he chose. Theoretically an heir could inherit a parcel of land/estate and have no financial means to keep it up.
An heir could voluntarily abjure a title. _URL_1_.
I am not aware of a means to force an heir out unless the parent filed a writ to have him declared a bastard. Until the 20th century bastards could not inherit a title or take from a parent who died intestate.
On teh Continent, in what we call France and some of teh German principalities, Sa;ic Law governed civil law issues including inheritance.
I am less familiar with Salic Law provisions
_URL_0_
| [
"The duke, a descendant through a morganatic marriage of the royal family of Württemberg, was the elder son of Albert's aunt, Princess Florestine of Monaco. Although he was ineligible to inherit the crown of his patrilineal ancestors in Germany, given the line of succession to the Monegasque throne at that time, th... |
why does coffee help a hangover? | Hangovers, in ELI5 terms, are a specific case of dehydration. Caffeine is a diuretic, meaning it makes you pee more, which doesn't help the dehydration causing you to feel like crap.
However, hangovers leave you feeling sluggish, tired and achey. Caffeine is a stimulant, which helps to perk your body up, helping you overcome several of the "worn down" symptoms of the hangover.
Caffeine also makes veins constrict a bit, which slows blood flow especially in the brain, which means it can do a little to help with headaches. | [
"Coffee enemas can cause serious side effects (some common to other types of enemas), including infections, sepsis, severe electrolyte imbalance, colitis, proctocolitis, salmonella, brain abscess, and heart failure. If the coffee is inserted too quickly or is too hot, it could cause internal burning or rectal perfo... |
why do diseases only do bad things to us? why are there no diseases/viruses that are actually good for us? | Yes, there are good diseases. For instance, retroviruses and bornaviruses account for 8-9% of the human genetic code, and the same is true for most mammals and birds. One pretty useful thing retroviruses help with is the formation of the placenta and differentiation early in fetal development. These genes have been proven to come from multiple strains of human endogenous retrovirus (herv), and suppressing them slows and hinders development and the ability to latch onto the uterine wall. Just one example of a beneficial virus, and 8-9% of our DNA comes from them.
There are a surprising number of retrovirus genes that protect and aid the development of the fetus. It is kinda strange, but it fascinates me. | [
"Common human diseases caused by viruses include the common cold, the flu, chickenpox and cold sores. Serious diseases such as Ebola and AIDS are also caused by viruses. Many viruses cause little or no disease and are said to be \"benign\". The more harmful viruses are described as virulent.\n",
"In \"Germs Go Gl... |
how does the water table work? i just did deep enough and then there's water? why aren't deep caves flooded then? | > I just did deep enough and then there's water?
basically. if you had a cup of water, and added sand until the top was dry, you would have a water table. you can do this near the beach. dig down a bit and the sand is wet.
the earth is a bit more complicated, though. for instance, certain materials can form a barrier to water. clay is quite famous for it. a layer of clay can trap the water and keep it lower than it normally would be, or elevate it so its closer to the surface than you would expect because the water can't slip through.
solid rock can also keep water out, and the water in the ground will go around it.
> Why aren't deep caves flooded then?
most of them are. the ones that aren't are the exception, and mines spend huge amounts of resources keeping water out.
most caves are formed by water. a small fissure in rock has water flow through it for millions of years and it slowly erodes it, opening the fissure wider and lower as gravity pulls it down. | [
"It is estimated that a cave cannot exceed in depth due to the pressure of overlying rocks. For karst caves the maximum depth is determined on the basis of the lower limit of karst forming processes, coinciding with the base of the soluble carbonate rocks. Most caves are formed in limestone by dissolution.\n",
"A... |
What kind of spices did the ancient Mesopotamians use? | From what we know (from texts and palaeobotanic studies), there were many spices that are also used in modern Middle Eastern cuisine, such as onion, garlic, coriander, cumin, fennel, cress, dill, mint, thyme, cardamom...
In addition, we have words for spices attested in the texts where we are not entirely sure what plant/spice they refer to.
I'm not a 100% sure that the word for sumac has been correctly identified, but it is a fair assumption that it would have been used in cooking. | [
"The ritual use of spices was common in the classical era, in many instances spices were used in oils by soaking them or creating fragrances by burning them. However many of the spices that became common place in the late classical period were spices that were originally from countries outside of Roman territory an... |
why after 30+ years of life do i still randomly choke on my own spit at random? | I've read that as we were evolving to allow for complex speech, the larynx dropped lower in our throats. This makes it a lot easier for us to choke, though. So it's just an annoying trade-off for being able to speak. | [
"According to Brittany, her mother also has an eating disorder and in an interview, Brittany describes how they would have \"the greatest time\" with \"chew and spit\"; chewing \"bags and bags of candy\" and spitting it out without swallowing. Her mother's experience of anorexia is touched upon in greater detail in... |
with websites like expedia, and the ease of access to the internet, what exactly do travel agents do nowadays? | My friend is one. She sells travel packages to people who just don't want to deal with it, and there are a lot of people like that. There are people who don't "use the internet" or "trust the internet", there are people who just want to go somewhere and don't want to bother with the details of finding a hotel, flight, car, etc. they just want to walk in to an office, talk to a real person and say: i want to take my family of 4 on a 2 week vacation in may, we want to go to Paris, can you get us there and arrange everything?
There'd also people who are going on their first vacation, first flight, etc. to some people planning flights is hard.
And finally there's also people who maybe don't have the confidence of organizing themselves. Maybe they don't speak the language that well. Maybe they're worried about shady hotels. Maybe maybe maybe.
They provide a service to all of these people and more.
My friend also hates her job because it's 99% a sales job. She's forced to upsell and to sell expensive packages. To an internet savvy person with some common sense you could arrange everything yourself for a better deal, but that's not their audience. | [
"In response, travel agencies have developed an internet presence of their own by creating travel websites, with detailed information and online booking capabilities. Travel agencies also use the services of the major computer reservations systems companies, also known as Global Distribution Systems (GDS), includin... |
How did WW1 armies know when individual soldiers died on the battlefield? | They kept records of these guys and their families. Each soldier wears tags identifying them, find a body with tags a telegram is dispatched. If they don't find a body but the soldier fails to appear or report in they are missing and after a while missing and presumed dead. | [
"The men at the front had to struggle with supply problems–there was a shortage of food; and disease was rife in the damp, rat-infested conditions. Along with enemy action, many soldiers had to contend with new diseases: trench foot, trench fever and trench nephritis. When the war ended in November 1918, British Ar... |
How many people were really being sacrificed every year in the Aztec Empire before the Spanish arrived? I’ve heard claims it was in the tens of thousands or much lower. | I'll try and cover a few of your specific points, starting with the fact *Apocalypto* did not intend to portray the Aztecs, but the Maya. The film does (poorly) mash in some aspects of Aztec sacrifice, if only to further its goal of being colonialist apologia and torture porn. Fortunately, the sheer awfulness of the movie makes it a good jumping off point to talk about actual practices of sacrifice.
To start with, there were slaves in the Aztec world and a portion of them did come from slave raids. The whole notion of actual warriors going out to get slaves for sacrifices, however, is a bit ridiculous. While slaves would sometimes be used for sacrifices in particular circumstances, the majority of sacrifices stemmed from war captives. Taking a captive was considered a rite of passage for a young warrior and a requirement for military and social advancement. Note, however, that simply snatching up some schmuck from a podunk village was not a standard practice; the expectation was taking a captive *in battle*. Also, later in the Imperial phase of the Aztecs, certain opponents became so little regarded that even taking several of them in battle earned little more than a shrug, as this passage from Sahagun illustrates:
> And if six, or seven, or ten Huaxtecs, or barbarians, were taken, he gained thereby no renown.
Conversely, taking captive from more formidable opponents, such as those from Atlixco and Huexotzinco (which were coincidentally in the hard-fought borderland with Tlaxcala), earned great acclaim. So the notion of Aztec warriors raiding villages too small to apparently even have maize fields does not make sense.
Once captives were taken there are some scant mentions of using cages. From the same book of Sahagun:
> And there in battle was when captives were taken. When it had come to pass that they went against and conquered the city, then the captives were counted, there, in wooden cages: how many had been taken by Tenochtitlan, how many by Tlatilulco...
So using cages was a real thing, but there's no indication they were anything but temporary measures. For instance, they were also used during the sale of slaves, or when holding prisoners during trials. Captives were not simply rounded up and kept indefinitely like cattle in pens. Instead, captives were treated, well, like slaves, to be housed by their captors until the time of their sacrifice.
Were those sarifices a public spectacle? Well, yes and no. Many of the sacrifices were public events, and some specifically so in a way that demonstrated the power of the Aztec state. Rulers and dignitaries of foreign, even enemy, nations would be invited to witness these displays as a form a intimidation.*Apocalypto* portrays these sorts of events as a wild bacchanal of primitives gyrating in a wild, unhinged frenzy. In fact, if we turn to sources like Duran or Sahagun, we see that even the most public and bloody ceremonies were highly regimented rituals of specific songs, dances, offerings, and adornments, each with its own meaning. There was an aspect of spectacle, but ultimately these were religious rites.
We can see the combination of somber and spectacle in accounts of the "gladiatorial" sacrifice which took place during Tlacaxipehualiztli. After weeks of preliminary rituals, captors would bring their captives to a particular *calmecac*, Yopico, in the Sacred Precinct. There the captor would lead his captive up to a raised platform upon which lay a large heavy stone. Tied to the stone and armed with a macuahuitl whose blades were feathers, the captive would face up to four elite warriors (and a fifth left-handed one if he managed to "defeat" the four), but would ultimately be sacrificed on that stone once he faltered.
So there's certainly some spectacle there and the whole notion of "gladiatorial" combat evokes the Colosseum, but there's some substantial differences. For one, there's some dispute as to the "public-ness" of this event. Sahagun mentions no one but the priests and the warriors, which does not preclude the presence of others. Duran, meanwhile, says the "entire city was present," although the location of the particular calmecac where the combat took place was a smaller building off in one corner of the Sacred Precinct, which present problems for mass viewing.
More importantly though, the intentions were different. Even this particular sacrifice, which was among the largest (dozens are mentioned as sacrificed over the course of a day) and the combat making it among the most dramatic, the core aim was not to provide tititallation, but serve both as a sort of graduation ceremony for warriors who had taken a captive and also a way of providing "sustenance" to the gods. On that latter part, just as important as the actual combat was the captor taking the blood of his sacrifice, collected by the priests in a bowl, and going from idol to idol having them take a "drink" from the bowl. Considering the symbolic impetus of Aztec warfare was to engage in battle in order to "feed" the gods, this act not only completed that divine onus, but the entire gladiatorial spectacle re-created the process of warfare/capture/sacrifice. This was not just bread and circuses, in other words.
| [
"Michael Harner, in his 1977 article \"The Enigma of Aztec Sacrifice\", cited an estimate by Borah of the number of persons sacrificed in central Mexico in the 15th century as high as 250,000 per year which may have been one percent of the population. Fernando de Alva Cortés Ixtlilxochitl, a Mexica descendant and t... |
how slow can light be? | Slow light is the propagation of an optical pulse or other modulation of an optical carrier at a very low group velocity. Slow light occurs when a propagating pulse is substantially slowed down by the interaction with the medium in which the propagation takes place.
In 1998, Danish physicist Lene Vestergaard Hau led a combined team from Harvard University and the Rowland Institute for Science which succeeded in slowing a beam of light to about 17 meters per second, and researchers at UC Berkeley slowed the speed of light traveling through a semiconductor to 9.7 kilometers per second in 2004. Hau later succeeded in stopping light completely, and developed methods by which it can be stopped and later restarted. This was in an effort to develop computers that will use only a fraction of the energy of today's machines.
In 2005, IBM created a microchip that can slow down light, fashioned out of fairly standard materials, potentially paving the way toward commercial adoption.
Lifted from _URL_0_ | [
"A Slower Speed of Light is a freeware video game developed by MIT Game Lab that demonstrates the effects of special relativity by gradually slowing down the speed of light to a walking pace. The game runs on the Unity engine using the own open source OpenRelativity toolkit.\n",
"Light propagates at 299,792,458 m... |
[Meta] Some thoughts on warnings | Rule #1 of reddit: Mods are dictators by nature of the system.
This sub understands that better than any around. Sounds like you were being a bit stone-minded about reposting an already removed comment. That *does* make perfect sense, and doesn't merit an extra rule in the list, as far as I'm concerned as a non-mod. The rules list is not meant to be a "Here is a point-for-point explanation of what is and is not appropriate". Else it'd be filled with every little arbitrary rule they could think of.
That's ridiculous. Rules of subreddits are not *laws*. They don't have to be enforced to the letter, or even posted at all.
I get that you think that it should be simple enough for a mod to simply message and ask courteously, but compound that by a thousands. That's how often they'd have to do it. Because you're just one user among thousands. When you've received two warnings already, I think a temp ban for the third is totally justifiable. | [
"BULLET::::- \"Warnings\" are messages explaining negative events, such as heavy acid rain falling on a world and therefore causing much damage there, medical problems with previous technological breakthroughs, major enemy military movements, or a toxic gas leak on a planet that results in losing the civilian popul... |
why do opera singers put so much vibrato on everything? is it the only way to get the volume they need? | Voice major here...
Vibrato ensures a continuous airstream from your diaphragm. It's an easy way to keep your muscles from gumming things up in the throat/jaw area, which can change the sound. Having your muscles truly loose and relaxed while singing makes for a truer more beautiful sound, and vibrato ensures that the muscles don't mess up the airstream. It's a healthy way to sing that will preserve stamina, something opera singers need to get through 4 hours of Wagner.
True ELI5?
Vibrating their voice like that forces them to keep their muscles loosey goosey, which makes singing easier and more beautiful.
| [
"Traditionally, however, the deliberate cultivation of a particularly wide, pervasive vibrato by opera singers from the Latin countries has been denounced by English-speaking music critics and pedagogues as a technical fault and a stylistic blot (see Scott, cited below, Volume 1, pp. 123–127). They have expected vo... |
why is it that current pop songs' lyrics are repetitive verses repeated over and over, compared to the pas,t when lyrics were very diverse with different verses? | Pop music is written around a formula that bastardizes the idea of the hook, which is the part of a song that draws you in and usually it's the part that gets stuck in your head. It's not a new idea for pop songs to just repeat the same lines over and over. It's been a popular method since the 1980s at least. Songs like Electric Boogie, Gonna Make You Sweat, Stayin' alive, etc. all depend on that initial chorus. | [
"Some of their lyrics are notable for their unusual meter patterns; a prime example of this is their 1972 hit \"Reelin' In the Years\", which crams an unusually large number of words into each line, giving it a highly syncopated quality.\n",
"Most of the songs have only a few verses and the majority of them are a... |
why is light the fastest thing in the universe and not any other wave? | when we use light in that statement we mean the entire spectrum, not just visible light. So essentially 'radiation' is the fastest thing in the universe | [
"In the abstract for her paper, \"Complex Speeds and Special Relativity,\" Asaro writes \"The quest to find faster‐than‐light particles has intrigued physicists for decades, though it has yet to turn up any real candidates. Even if a superluminal universe does exist, we have no way to reach it given that we must go... |
What was European cooking like before the introduction of Asian spices? | While you wait for more qualified people to answer, here's a section of the FAQ that may tide you over:
_URL_5_
Also, you'll need to be a little more specific about time frame and/or location within Europe, as well as which level of society you're asking about. My understanding is that in 12th-century England and northern France, for the lower classes, they ate a mostly vegetarian diet of barley, rye, beans, and leafy vegetables like kale and spinach. Herbs like rosemary, lavender, basil, sage, thyme, and garlic were all available through foraging. People also ate flowers, something we don't do much nowadays. People drank water, small beer (produced on a household level, often by women), cider, mead, and whey. Meat was rare, especially beef since cows needed a lot of food. Pork was relatively common since people could let their pigs wander and feed in the woods for most of the year. Hunting and fishing were tightly regulated by the local lord, who also usually had a monopoly on millstones and ovens for making bread. Overall their diet was pretty good, lots of high quality protein and fiber.
Reading you may be interested in:
[Fast and Feast: Food in Medieval Society](_URL_0_) (Examines cultural attitudes toward food.)
[Food in Medieval Times](_URL_4_) (More focused on what was generally available to the average person.)
[The Art of Cookery in the Middle Ages](_URL_3_) (This is more focused on the upper classes.)
EDIT: Here is some information concerning [forest laws](_URL_1_) and [charters of free-warren](_URL_2_), which should help cast some light on the kinds of restrictions that common people faced in finding food.
Also, as mentioned below, I forgot to say that dairy in general was pretty important. It was a good source of nutrition, especially since cheese keeps forever. Cows were generally more valuable alive and producing milk than dead and eaten. | [
"Beginning in the 16th century, successive waves of Europeans—the Portuguese, Spanish, Dutch and British—sought to dominate the spice trade at its sources in India and the 'Spice Islands' (Maluku) of Indonesia. This meant finding a way to Asia to cut out Muslim merchants who, with their Venetian outlet in the Medit... |
Why do women have 2 ovaries? Why can't there be just one ovary? | The same question can e asked of why men have two testicles - the are developmentally synonymous. Procreation is the fundamental root of evolutionary biology, thus our ancestors with two gonads were likely more successful in reporducing | [
"Birds have only one functional ovary (the left), while the other remains vestigial. Ovaries in females are analogous to testes in males, in that they are both gonads and endocrine glands. Ovaries of some kind are found in the female reproductive system of many animals that employ sexual reproduction, including inv... |
What was the mainstream Roman take on the god of the Judeans? | The average Roman didn't think much of Judaism, because they didn't think of them at all. Among those who actually cared about such matters, Judaism was likely seen as another weird Eastern cult, but with respectable venerability. Jews themselves had a poor reputation, at least going by Tacitus, who stereotyped them as bandits, essentially. However, I should note that this is not particularly unusual of Tacitus, who was pretty grumpy.
EDIT: I should probably provide quotes. Two lengthy Tacitus quotes, followed by a quick Juvenal and a Varro that is quite interesting:
Great, irrelevant quote from Tacitus: "This force was accompanied by twenty cohorts of allied troops and eight squadrons of cavalry, by the two kings Agrippa and Sohemus, by the auxiliary forces of king Antiochus, by a strong contingent of Arabs, who hated the Jews with the usual hatred of neighbors..." Some things don't change. More relevant quotes:
Tacitus (again)
> "Moses, wishing to secure for the future his authority over the nation, gave them a novel form of worship, opposed to all that is practised by other men. Things sacred with us, with them have no sanctity, while they allow what with us is forbidden. In their holy place they have consecrated an image of the animal by whose guidance they found deliverance from their long and thirsty wanderings. They slay the ram, seemingly in derision of Hammon, and they sacrifice the ox, because the Egyptians worship it as Apis. They abstain from swine's flesh, in consideration of what they suffered when they were infected by the leprosy to which this animal is liable. [etc]"
More pointedly,
> This worship, however introduced, is upheld by its antiquity; all their other customs, which are at once perverse and disgusting, owe their strength to their very badness. The most degraded out of other races, scorning their national beliefs, brought to them their contributions and presents. This augmented the wealth of the Jews, as also did the fact, that among themselves they are inflexibly honest and ever ready to shew compassion, though they regard the rest of mankind with all the hatred of enemies. They sit apart at meals, they sleep apart, and though, as a nation, they are singularly prone to lust, they abstain from intercourse with foreign women; among themselves nothing is unlawful. Circumcision was adopted by them as a mark of difference from other men. Those who come over to their religion adopt the practice, and have this lesson first instilled into them, to despise all gods, to disown their country, and set at nought parents, children, and brethren. Still they provide for the increase of their numbers. It is a crime among them to kill any newly-born infant. They hold that the souls of all who perish in battle or by the hands of the executioner are immortal. Hence a passion for propagating their race and a contempt for death. They are wont to bury rather than to burn their dead, following in this the Egyptian cus tom; they bestow the same care on the dead, and they hold the same belief about the lower world. Quite different is their faith about things divine. The Egyptians worship many animals and images of monstrous form; the Jews have purely mental conceptions of Deity, as one in essence. They call those profane who make representations of God in human shape out of perishable materials. They believe that Being to be supreme and eternal, neither capable of representation, nor of decay. They therefore do not allow any images to stand in their cities, much less in their temples. This flattery is not paid to their kings, nor this honour to our Emperors. From the fact, however, that their priests used to chant to the music of flutes and cymbals, and to wear garlands of ivy, and that a golden vine was found in the temple, some have thought that they worshipped father Liber, the conqueror of the East, though their institutions do not by any means harmonize with the theory; for Liber established a festive and cheerful worship, while the Jewish religion is tasteless and mean.
From Juvenal (VI.542-547):
> No sooner has that fellow departed than a palsied Jewess, leaving her basket and her truss of hay,[68] comes begging to her secret ear; she is an interpreter of the laws of Jerusalem, a high priestess of the tree,[69] a trusty go-between of highest heaven. She, too, fills her palm, but more sparingly, for a Jew will tell you dreams of any kind you please for the minutest of coins.
By Juvenal's standards, that is fairly tame. I think that sums up the "weird eastern cult" aspect.
Varro's opinion was rather higher. Transmitted through Augustine:
> For more than 170 years, the Romans of old worshipped the gods without an image. If this practice had remained down to the present day’, he [Varro] says, ‘the gods would have been worshipped with greater purity’ (castius dii observarentur). In support of thisopinion, he cites, among other things, the testimony of the Jewish nation
> (frg. 18Cardauns; Aug.,The City of God 4.31).
Add that to the long list of why I want to read Varro's *Divine Antiquities*. | [
"The \"Religio Romana\" (literally, the \"Roman Religion\") constituted the major religion of the city in antiquity. The first gods held sacred by the Romans were Jupiter, the most high, and Mars, god of war, and father of Rome's twin founders, Romulus and Remus, according to tradition. The goddess Vesta became an ... |
What would happen if we started pumping huge amounts of water into the middle of the Sahara Desert? | For an understanding of how to do this and make it work, ie keep the water--in this case seas water--there and grow things with it, see the [Sahara Forest Project](_URL_0_). Their proposals involve using solar power to desalinize sea water, that would then be used to grow crops and trees, initially in an onsite greenhouse, and later outside around the facility. They opened a pilot site in Qatar last year to test the system. | [
"The first person to suggest flooding large parts of the Sahara desert was the writer Jules Verne in his book \"Invasion of the Sea\". Plans to use the Qattara Depression for the generation of electricity reportedly date back to 1912 from Berlin geographer Albrecht Penck. \n",
"Scientists agree that the existence... |
if a room temperature object is left in outer space for an hour, would it come back colder, warmer, or the same temperature? | Heat is also transferred by radiation, which does not require a medium (particles, like air/water/etc). Your object in space would radiate heat and start to cool, but you also have to account for incoming radiation (from the Sun, for one example). So, your answer depends quite a lot on where you put the object. If the object is radiating more heat than it's receiving, it will get colder. | [
"If changes in external temperatures or internal heat generation changes are too rapid for the equilibrium of temperatures in space to take place, then the system never reaches a state of unchanging temperature distribution in time, and the system remains in a transient state.\n",
"Human comfort levels must also ... |
Is there such a thing as being "in the zone" or "having momentum" in sports? | There is a psychology term known as [Flow](_URL_0_)
> Flow is the mental state of operation in which a person in an activity is fully immersed in a feeling of energized focus, full involvement, and success in the process of the activity. Proposed by Mihály Csíkszentmihályi, the positive psychology concept has been widely referenced across a variety of fields.[1]
> According to Csíkszentmihályi, flow is completely focused motivation. It is a single-minded immersion and represents perhaps the ultimate in harnessing the emotions in the service of performing and learning. In flow, the emotions are not just contained and channeled, but positive, energized, and aligned with the task at hand. To be caught in the ennui of depression or the agitation of anxiety is to be barred from flow. The hallmark of flow is a feeling of spontaneous joy, even rapture, while performing a task[2] although flow is also described (below) as a deep focus on nothing but the activity - not even oneself or one's emotions.
> Colloquial terms for this or similar mental states include: to be on the ball, in the moment, present, in the zone, wired in, in the groove, or keeping your head in the game.
Whether there are hormonal changes going on is something I can't help you with but it seems likely. | [
"Roy Palmer suggests that \"being in the zone\" may also influence movement patterns as better integration of the conscious and subconscious reflex functions improves coordination. Many athletes describe the effortless nature of their performance while achieving personal bests.\n",
"The concept of \"being in the ... |
AskScience Cosmos Q & A thread. Episode 1: Standing Up in the Milky Way | When I majored in astrophysics, I was taught that the universe is 13.7 billion years old. In Cosmos tonight, Neil deGrasse Tyson was saying 13.8 billion years. Has it really been that long since I was in university? | [
"\"Standing Up in the Milky Way\" is the first aired episode of the American documentary television series \"\". It premiered on March 9, 2014, simultaneously on various Fox television networks, including National Geographic Channel, FX, Fox Life, and others. The episode is presented by the series host astrophysici... |
If your body produces antibodies after defeating a pathogen indefinitely, when an individual gets exposed to many pathogens throughout their life, will they have a larger antibody density in their blood? Is there a limit to this? | Antibodies are made as you require them. They are made by lymphocytes, after an infection you havea low number lymphocytes called memory cells in your blood these can build the antibodies required if you are exposed to the pathogen again.
The original process of producing an antibody for an infection is a random process.
Immunity comes about because correct antibodies can be produced faster the second time you have an infection. | [
"Even if the host does develop antibodies, protection might not be adequate; immunity might develop too slowly to be effective in time, the antibodies might not disable the pathogen completely, or there might be multiple strains of the pathogen, not all of which are equally susceptible to the immune reaction. Howev... |
why aren't there any laws limiting the use of plastic? | Because people want plastic things, a lot. The innovation of plastic products completely changed the world. People in general don't want to stop using plastic. | [
"Recycling, banning, and taxation fails to adequately reduce the pollution caused by plastic bags. An alternative to these policies would be to increase extended producer responsibility. In the US, under the Clinton presidency, the President's Council on Sustainable Development suggested EPR in order to target diff... |
In "The Dialectic of Sex," Shulamith Firestone claims that childhood was essentially an invention of the 15th century, and that before that point male children were treated as adults and functioned perfectly well in adult society. Is this true? | I'm not familiar with Firestone's book, but I've written a few times on childhood and adolescence in the premodern world here on AH.
* [Historiography of children and childhood](_URL_0_)
* [Is adolescence an invention of the 20th century?](_URL_1_) (This has more to do with teenage-hood as a distinct life stage)
Mentioned in the second post, Shahar and Hanawalt provide some of the clearest evidence that medieval boys, specifically, were not merely "little men." They show how boys (into teenagehood!) did spend some of their leisure time engaging in some activities practiced by men--but they were still excluded from some, and they still spent some of their time in children's/women's activities. Latin chroniclers also distinguish between youths and boys of "full maturity."
Parents writing letters to their sons at university (think ages 15-20) seem quite sure that those sons are not ready to be fully functioning adults, what with how they throw money away on frivolties and neglect their studies and brawl violently at bars. | [
"Her book \"Meanings of Sex Difference in the Middle Age: Medicine, Science, and Culture\" (1993) was groundbreaking in its examination of sex and gender, and has deeply influenced subsequent scholarship. Cadden examines the discussions of sexual difference from Aristotle through the fourteenth century, revealing a... |
Is time dilation the same at every black-hole event horizon? | Might I be able to also ask a question regarding black holes, their shape etc.?
From what I understand, there's a region on the edge of the event horizon is a photon sphere where photons moving on a tangent to this will become trapped in orbit.
However when I've seen pictures regarding black holes - particularly showing the 'corona' around the event horizon where light behind the hole is bending around it - it is shown as just that: a corona-like light with a void in the middle.
How can the photon sphere be just that - spherical - yet not actually show up as a mass of photons when viewed in xray /infra-red etc? Surely if these photons are in a sphere around the event horizon it would appear almost like a star, right? | [
"There are real phenomena that cause time dilation similar that of a stasis field. Extremely high velocities approaching light speed or immensely powerful gravitational fields such as those existing near the event horizons of black holes will cause time to progress more slowly. However, there is no known theoretica... |
why is it so difficult for the medical community to give a straight answer about how much a procedure/appointment/etc. will cost? | The doctors and nurses don't even *know* how much shit costs. They just say what work they've done & the billing department handles the prices.
Billing can't give you a straight answer because they have different rates for cash payments or insurance. Every insurance company negotiates a set of rates they'll pay for procedures but how much you're left paying depends on the terms of your insurance plan. Then, if you're poor, you might be able to negotiate an even *lower* price so the hospital can at least get *something* out of you.
The whole system is confusing and inefficient. Those inefficiencies only serve to drive costs up while making insurance companies rich. This is one of the many reasons that people think a single-payer system - where the government is the only insurer for everyone - would be superior. | [
"The American Medical Association showed that asking simple single item questions, such as \"How confident are you in filling out medical forms by yourself?\", is a very effective and direct way to understand from a patient's point of view how they feel about interacting with their healthcare provider and understan... |
do programs like lumosity have any measurable benefit to cognitive abilities? or is it all just hype? | Using Lumosity regularly makes you better at Lumosity. It might be of more benefit to your cognition than staring at a wall and picking your nose, but it's mostly hype and pseudoscience | [
"Kable researches cognitive neuroscience. His work has suggested that an individual's approach to risk in decision making is correlated with the anatomical structure of the brain. Another of Kable's projects concluded that \"Brain Training\" using Lumosity software “appears to have no benefits in healthy young adul... |
How was helium identified from the continuous spectrum of the sun? | The sun's photosphere is cooler than the regions below it, creating absorption lines. If you point a spectrometer at the sun you don't get a continuous spectrum, you get a continuous spectrum superimposed with black lines where the particular wavelength was absorbed by the cooler upper atmosphere. Those absorption lines are in the exact place that emission lines are, so if we see absorption lines in the sun that we haven't been able to find a matching emission line then we know we have an element in the sun that we have yet to find and get emission lines for. Here is a picture of the whole visible wavelength spectrum of the sun _URL_0_ | [
"The first evidence of helium was observed on August 18, 1868, as a bright yellow line with a wavelength of 587.49 nanometers in the spectrum of the chromosphere of the Sun. The line was detected by French astronomer Jules Janssen during a total solar eclipse in Guntur, India. This line was initially assumed to be ... |
What would the ramifications of a lack of causality be? | Unpredictability. The equations of motion lose existence and uniqueness. Given a certain initial condition at time t, there might not exist a solution to later time, or there might be infinite equally valid. Essentially the Universe doesn't know what to do with itself, and even if it does, there is no way of predicting anything even having knowledge of the equations of motion and initial condition. Physics is dead.
That loss of existence and uniqueness actually occurs has been studied for various cases, including the motion of a rigid ball in a spacetime with a wormhole allowing timetravel (see e.g. the works of Novikov & Thorne), or classical field theories in the presence of CTCs.
The exceptions are free theories, but these are boring, no actual physics can happen in them. As soon as you add interactions of any kind it's over.
Another sort of consideration comes from thermodynamics. We have a second law because our Universe has two temporal extremities with different entropies. So entropy increases when moving from one to the other; we call the low-entropy one the Big Bang and the direction of increasing entropy gives the arrow of time, and interesting stuff happens following the Universe in this direction.
If you have a region with CTCs where, say, you can think of time as a circle, there is no way of course for entropy to always increase in one direction. The most probable situation is to always have constant maximum entropy, that is thermal equilibrium. | [
"Causal determinism has a strong relationship with predictability. Perfect predictability implies strict determinism, but lack of predictability does not necessarily imply lack of determinism. Limitations on predictability could be caused by factors such as a lack of information or excessive complexity. \n",
"Som... |
why do vodka sodas dehydrate me? | The metabolism of alcohol requires the presence of water, and alcohol itself is a diuretic which results in less available water in your body.
Edit: To expand on this, the amount of water in your mixed drink is probably insufficient to hold off dehydration after your body has processed the alcohol. Everyone has an individual water requirement to maintain themselves. You may just not be reaching yours when you drink, and have to compensate by drinking more water in the morning. | [
"In some countries, black-market or \"bathtub\" vodka is widespread because it can be produced easily and avoid taxation. However, severe poisoning, blindness, or death can occur as a result of dangerous industrial ethanol substitutes being added by black-market producers. In March 2007 in a documentary, BBC News U... |
why when running on a treadmill usually i'm really tired at 15 min mark, almost dead at 20 min, and ok at 30 min mark ? | It actually comes from where your body gets it's energy from. For the first 15-20 minutes your body is burning it's glycogen storage which comes from sugar. After your body has run out of its primary source of energy it runs on fumes until your body starts burning your fat storage. This doesn't kick in until around that 30 minute mark because your body has to turn that fat back into sugar for it to use which takes a while.
Source: avid runner for 10+ year and worked in a running store for almost 8 years and have had to explain this to people lots | [
"BULLET::::- Treadmill training – Many treadmills have programs set up that offer numerous different workout plans. One effective cardiovascular activity would be to switch between running and walking. Typically warm up first by walking and then switch off between walking for three minutes and running for three min... |
where did the term "fired" originate from? | [Etymology Online](_URL_0_) says it is recorded by 1885 (with out; 1887 alone) in American English. This probably is a play on the two meanings of discharge (v.): "to dismiss from a position," and "to fire a gun," influenced by the earlier general sense "throw (someone) out" of some place (1871). To fire out "drive out by or as if by fire" (1520s) is in Shakespeare and Chapman. Fired up "angry" is from 1824 (to fire up "become angry" is from 1798). | [
"The term \"feu\" (French for \"fire\" from the Latin \"focus\" meaning \"hearth\") meant, especially in the Middle Ages, the hearth, first in the strict sense (the place where the fire burns) and figuratively: the family home (cf. the expression \"without fire or place\") or the family itself. Very quickly, it was... |
What rank would a soldier have to be to avoid going 'over the top' in WWI? | That's a very interesting question, and relates a lot to a common perception that, once a certain level of authority is reached, the individual is less likely to participate in combat.
That is a very generalised view, of course, and as such not entirely correct. An army is a very rigid organization and must be tightly controlled and led. The closer that leadership is to the fighting, the more effective it can be. The balance, of course is to not expose high ranking leadership to the dangers of the front unnecessarily. Also, the larger formation one commands would dictate having to be further removed from the front on the basis of the scale of numbers a Division, Corps or Army commander would be dealing with.
There also lies a difference in the role of particular persons-what is known as "the Divisional Wedge"- which describes the ratio of those engaged in combat to those supporting combat operations. A Lt Col as a battalion commander would very likely advance with his men, while a Lieutenant assigned to General Headquarters might not ever hear a shot fired in anger. Likewise for NCO's. A farrier Corporal would be well removed from fighting, performing his job of shoeing horses, whilst a Sergeant in an infantry platoon would certainly see his fair share of the war.
Maj Gordon Corrigan illustrates that even high rank did not exempt one from the dangers of the war: "Altogether four British lieutenant generals, twelve major generals and eighty-one brigadier generals died or were killed between 1914-1918. A further 146 were wounded or taken prisoner. Whatever else the generals were doing, they were certainly not sitting in comfortable chateaux." *Mud, Blood and Poppycock* Cassell Press, 2003. | [
"BULLET::::- Many of the generals of World War I had experience in combat, but only from the days before trench warfare became widespread. Because of this, officers lacked the experience that in the past had made it viable to command troops from a distance.\n",
"During World War II, he served in the Royal Artille... |
how do some people become the mod of dozens of subreddits? | You'd have to ask the people who made the decision to add them, we don't know. The thought process for each individual mod invite was probably different.
I'm not sure but it's also possible that they did stuff like CSS work. There are some people who do design and CSS stuff for lots of subreddits so they have mod powers, but they don't actually moderate much. We had /u/gavin19 on our staff here for a while while he helped us out with some stuff, for example, and we could have left him on if we wanted even though he never did any moddy work. | [
"Subreddits are overseen by moderators, Reddit users who earn the title by creating a subreddit or being promoted by a current moderator. These moderators are volunteers who manage their communities, set and enforce community-specific rules, remove posts and comments that violate these rules, and generally work to ... |
What was the video-recording format in the USSR/Ex-socialist countries ? Was there an equivalent to VHS ? | I'm not an expert on The Soviet Union but I have a strong interest in and experience with tech. So a Soviet expert may be able to add a lot to the discussion. But to quickly answer your main question, the main format used popularly in the USSR was VHS and the VCR.
There were other forms of magnetic recording devices used mostly by professionals but I don't know much about them. You seem most interested in personal use though.
According to several US news articles the machines first appeared by being brought back by those who had travelled to the West. Demand for the devices began to grow and video parlors had opened by 1985 using the VHS format.
Here's a [link](_URL_0_) to a book called "Split Signals" by Ellen Propper Mickiewicz.
This book was published in 1988 and she wrote about television in the USSR during this time and has a section just on VCR production and usage. Highlighted is a reference to the Elektronika VM-12 which was one of the first Soviet produced VCRs.
Electronika is a brand name used to describe consumer products created by Soviet military industrial engineers. It's still in use today in Belarus. Although according to Mickiewicz the VM-12 was produced in Voronezh a Russian city south of Moscow.
Unfortunately I'm unaware of the ability of these Soviet produced machines to record as well as playback. The way Mickiewicz describes the machines it seems like the government wanted to be able to control what was available and supplant a growing black market for video watching with approved materials.
Links to contemporary news articles:
*[Chicago Tribune](_URL_1_) Discusses early use and has some pretty slanted views on Vodka vs Video as a hobby.
*[LA Times](_URL_2_) Discusses copy protection and privacy.
*[Baltimore Sun](_URL_3_) Written by a Soviet immigrant to America, it has an interesting personal perspective on the format and the exchange of culture it allowed.
| [
"The first video cassette recorder (VCR) to become available was the U-matic system, released in September 1971. U-matic was designed for commercial or professional television production use, and was not affordable or user-friendly for home videos or home movies. The first consumer-grade VCR to be released was the ... |
; why can't they just give the 12 boys and the football coach who were found in the cave in thailand oxygen masks so they can swim out? why do they need to teach them to dive or wait for the flood to recede? | There's a lot more to diving than just putting on a mask and swimming. For example, if one of the boys gets scared and holds his breath, then ascends, his lungs could rupture quite easily. They need to make sure that the boys can dive safely before they can use that as an escape method. | [
"On 23 June 2018, a group of twelve boys aged between 11 and 16, who went to explore Tham Luang Nang Non with their assistant football coach, aged 25, went missing. The group was found 10 days later. They were part of a local junior football team. The cave they entered became flooded. Thai Navy SEAL divers had been... |
- why is it so hard for companies doing political surveys to actually predict the elections? | Really? The _vast_ majority of polling is very accurate - we just only pay attention to it in the few situations where the polling was "wrong".
Polling is difficult because you are trying to take a small sample of people and extrapolate what you learn from them to a population as a whole. Ensuring that the sample is representative of the population is tricky, as is making sure that you get honest answers from those people.
Reputable pollsters work very hard to try to eliminate bias in their questions and their samples to make the results as accurate as possible, but they know that anytime you sample you won't get perfect results. That is why they also publish confidence intervals and margins of error - how accurate they feel the polling to be. | [
"In politics it is common to attempt to predict the outcome of elections via political forecasting techniques (or assess the popularity of politicians) through the use of opinion polls. Prediction games have been used by many corporations and governments to learn about the most likely outcome of future events.\n",
... |
why is human diet so complex? | A big part is just convienece and choice. Animals with "higher" capacity for reason can figure out optimal ways to get food and therefore the option to be picky.
Most animals don't have the range primarily because they're both evolved to live in a certain area and they have a lower count of things that they're required to to on a day to day basis.
Most animals can be lumped into predator/prey and have diets that fit their lifestyle and activities accordingly.
Other animals, like our cousins the chimp which fall into both and have a wider range of day to day activities and behaviors, actually do have a pretty diverse diet. They eat lots of plants but they also eat eggs, honey, meat, etc.
Humans don't really "NEED" a diverse diet. We just choose to have one. | [
"Humans are omnivorous, capable of consuming a wide variety of plant and animal material. Varying with available food sources in regions of habitation, and also varying with cultural and religious norms, human groups have adopted a range of diets, from purely vegan to primarily carnivorous. In some cases, dietary r... |
What killed off the mega fauna? | Traditionally this has been ascribed either to the influence of humans on the environment or climate change, although occasionally disease has been tossed around as a hypothesis. Lately, many scientists have been siding with the climate change view.
[This study suggests otherwise.](_URL_0_) It would appear from global analysis of extinctions of megafauna over time that while most of these species had already survived numerous climatic shifts at the time of their demise, nearly all coincided with the earliest evidence of human presence in the area. It seems no accident that (large-bodied) mammoths survived later in North America, and were extinct within a few thousand years of humans reaching the continent.
Remember that most of the species that died off, the 'megafauna' were large creatures with metabolisms that required large amounts of food and had slow gestation and growth rates. Driving them to extinction by hunting wouldn't have required killing every single one, only enough to reduce the population by a little bit each year. The populations would have been particularly devastated if too many females were killed, as we see with modern day elephant populations. Also, the presence of a large population of humans foraging and gathering edible plant material might have reduced the amount of nutrition available to the animals, although I don't know if they would have been enough to have an impact on that or even ate the same vegetation. Certainly a systematic, if slow, reduction of the prey populations would have resulted in a decrease of large predators like dire wolves and cave lions, which probably suited the early humans just fine.
Another thing to note is that the extinction probably didn't happen very quickly. There would never have been a generation that saw the megafauna disappear. There would have been fewer and fewer mammoths each generation, until finally only grandpa remembered having seen one. The mammoths weren't literally all being slaughtered, they were just having more and more trouble finding mates and being able to maintain a sustainable population.
Hope that helps a bit. I'm not an expert on the topic, although I do follow it closely and know a fair bit about it. I've heard evidence supporting both cases and while I see this one as more likely, I don't deny that climate change may well and probably did add to the decrease in megafauna populations.
Interesting fact: the only continent with a diversity of sustainable megafauna populations is Africa, the continent on which humans evolved... Currently, biodiversity of large mammals is at a critical low, thanks to the Pleistocene extinctions. Ecosystems like the Siberian tundra and the American west are barely sustainable because of the absence of the megafauna that were once part of that equilibrium. At least I have read this several times, someone might be able to elaborate or correct me on that.
Edit: you tagged your question as biology, but it might be more accurately tagged as paleontology. I know the paleontology tag doesn't appear in the sidebar, but there is one! | [
"During the American megafaunal extinction event around 12,700YBP, 90genera of mammals weighing over became extinct. The extinction of the large carnivores and scavengers is thought to have been caused by the extinction of the megaherbivore prey upon which they depended. The cause of the extinction of the megafauna... |
ip addresses, subnet masks and why some ip addresses can see others on the same network? | An IPv4 address is just 4 bytes; each number between the dots is in a range of 0 to 255.
Take 192.168.60.1
In binary that's 11000000.10101000.00111100.00000001.
Now take a subnet like 255.255.224.0
In binary that's 11111111.11111111.11110000.00000000
Notice how all of the bits are together? The part of the address that identifies the network are where the ones are. The part that describes the address on the network are where the zeros are. This is why it's called a subnet [mask](_URL_0_)
So, with our previous example
11000000.10101000.00111100.00000001 - IPv4 Address
11111111.11111111.11110000.00000000 - Subnet mask
11000000.10101000.00110000.00000000 - Network part (192.168.48.0)
00000000.00000000.00001100.00000001 - Node address of node on network | [
"Today, IP addresses are associated with a subnet mask. This was not required in a classful network because the mask was implied by the address itself; Any network device would inspect the first few bits of the IP address to determine the class of the address and thus its netmask.\n",
"The term \"subnet mask\" is... |
When accelerating close to c, the universe appears to contract. We see the universe as expanding. Is it possible that this is some related phenomenon and that the universe isn't actually expanding? | No, these are two different phenomena (which are, by the way, both accounted for in the mathematics, so aren't being mistaken for one another!). Two observers who are moving at different speeds will measure lengths differently - this is what you're referring to with contraction - but there's no such set-up in cosmology, we're essentially at rest (in our own reference frame) and watching galaxies and galaxy clusters move away from us in all directions. | [
"Since the Hubble \"constant\" is a constant only in space, not in time, the radius of the Hubble sphere may increase or decrease over various time intervals. The subscript '0' indicates the value of the Hubble constant today. Current evidence suggests that the expansion of the universe is accelerating (\"see\" Acc... |
is space observation in real time? | everything you see is delayed. you seeing the sun is 8 minutes delayed. you watching the moon is 1.3seconds delayed. you looking at jupiter yesterday was 35-52minutes delayed. you looking at the North star 323 YEARS delayed. when you look thru a telescope at andromeda galaxy, you're looking 2.25 million years delayed
you reading this text on the screen is 0.0000000001 seconds delayed from when the computer monitor first displayed it. | [
"In each reference frame, an observer can use a local coordinate system (usually Cartesian coordinates in this context) to measure lengths, and a clock to measure time intervals. An event is something that happens at a point in space at an instant of time, or more formally a point in spacetime. The transformations ... |
Are there any cells in the human body that don't need oxygen? | Red blood cells! It actually makes quite a bit of sense, because red blood cells exist in order to transport oxygen, and if they required oxygen, they would be much less efficient in that endeavor. | [
"Oxygen is needed by almost all organisms for the purpose of generating ATP. It is also a key component of most other biological compounds, such as water, amino acids and DNA. Human blood contains a large amount of oxygen. Human bones contain 28% oxygen. Human tissue contains 16% oxygen. A typical 70-kilogram human... |
What were the different techniques used for making swords across different cultures and time periods? | You're not the only one who loves swords! I was just saying the other day how much I miss the old *Highlander* TV series, but anyway... here's my quick round-up of posts discussing sword-making techniques. If anyone remembers any more, add the link as a reply & we'll create an entry in the "popular questions" wiki. - thx!
[How quickly did swords become too blunt to be effective during battle?](_URL_6_) (probably my all-time favourite post)
[what is the most effective sword/swordsmithing process that history has seen?](_URL_4_)
[Did any nation/culture even begin to approach the level of sword-making of Japan?](_URL_0_)
[What would be the primary differences between a cheap sword and an expensive sword, taking into account different time periods and methods of manufacture?](_URL_3_)
[Thursday Focus | Weaponry](_URL_1_)
[I just watched a NOVA episode on Ulfberht viking swords. There doesn't seem to be much about them elsewhere. Does anyone know a bit more about them, and maybe others like Ingelrii swords?](_URL_5_)
[Armor and/or weapon making resources? (Books, webpages, documentaries, articles?)](_URL_2_) | [
"Italian martial arts is the use of weapons (swords, daggers, walking stick and staff). Each weapon is the product of a specific historical era. The swords used in Italian martial arts range from the gladius of the Roman legionaries to swords which were developed during the renaissance, the baroque era and later. S... |
why do cities restrict the maximum height of structures? | There's quite a few reasons.
* Higher buildings mean a denser downtown core, causing greater traffic and possibly pollution issues as people come to work from bedroom communities and search for a place to park. So unless you have good public transport (which can be quite expensive to build if not in place already), concentrating things too much can be problematic.
* They block light and create major wind tunnels.
* They can go against the character of the place they're in. For example, some Caribbean island residents want to retain their island's quaintness and don't want to turn it into a mass of forty-story condo buildings so they have a "palm tree maximum height" rule.
* They can be more prone to safety problems like life-taking fires (e.g. 9-11) or earthquake response.
* The ground underneath them might not be suitably strong enough. | [
"Building height: 2.5 m (8' +/-) to 7.5 m (24' +/-) is common. Height is primarily limited by the capability of the wall panel to support the wind load. Height may be limited in narrow buildings due to shear capacity limit in the gable endwalls.\n",
"Among the restrictions in force within the zone is a ban on the... |
why are the soles of our feet so sensitive if they’re the main (and often only) point of contact with the ground? | Most likely because you wear shoes which keep your feet baby soft.
My kids go barefoot a lot and can walk across gravel without a problem. | [
"The soles of the feet are extremely sensitive to touch due to a high concentration of nerve endings, with as many as 200,000 per sole. This makes them sensitive to surfaces that are walked on, ticklish and some people find them to be erogenous zones.\n",
"The sole is a sensory organ by which we can perceive the ... |
Did 13th century English knights fight on foot? | This answer focuses on the Anglo-Norman period, so earlier than the 13th century. But since OP was interested in English knights fighting on foot before the 14th century, I guess this will still be of interest.
In "Warfare under the Anglo-Norman Kings 1066-1135", Stephen Morrillo argues that combined arms tactics was central to many battles in this period, and also points out that sometimes dismounted knights played the part of the heavy infantry. In particular, dismounted knights appear in the Battle of Tinchebrai (1106), the Battle of Brémule (1119) and the Battle of Bourgthérolde (1124), although often along mounted knights and other infantry. Although the example of three battles seems to be quite small, considering the fact that battles were rare in this period (Morillo counts 7 battles, C. W. Hollister counts 5 battles of significance), this actually accounts for a significant number of Anglo-Norman battles.
So why did this dismounting occur? A knight on horseback can easily retreat, while a knight on foot has less chance of escaping a rout unharmed. Forced into this situation, a dismounted knight must either conquer or die. Indeed, this is often the reason given in the sources for the dismounting of knights. Dismounting has a psychological effect, helping to counteract the fear of harm and death that pervaded every battlefield. In particular, having the knights, the military elite, join the battle lines on foot seems to have been massively encouraging to the common infantry as well. Leaders would often be part of the dismounted to further boost morale. For example, King Henry I seemed to have been on foot in the Battle of Tinchebrai and Brémule, and at Bourgthérolde, Odo Borleng was dismounted with the knights under his command. In this case, dismounting can be done to reinforce and stiffen an existing infantry line, instead of making up the entire infantry line themselves.
As for how the Anglo-Norman army was able to put this into practice, Morillo argues that it stems from the relatively more centralized nature of Anglo-Norman government. He argues that the superiority of medieval cavalry actually stems from the inferior quality of medieval infantry, which requires cohesion brought about by a strong military tradition and/or professional training, both of which were hard to provide in medieval Western Europe. However, due to the more centralized nature of the Anglo-Norman realm and the professionalism of the Famillia Regis (the king's household), there was a strong core force of knights who could function as effective heavy infantry when dismounted.
On the other hand, in the article "Battles in England and Normandy, 1066-1154", Jim Bradbury argues that the dismounting of knights wasn't unique to the Anglo-Normans, but was in fact common in Western Europe. He cites several earlier examples of dismounted knights (such as the Battle of the Dyle in 891) and argues that it grew out of ordinary Frankish tactics, as part of the combined arms response (along with archers and mounted knights) to the threat of a cavalry charge.
This suggests that the practice of dismounting was not uncommon amongst English knights before the 14th century, an might not even be unique to the English. Dismounting was done as part of a wider combined arms battle plan, and deliberately organised. In these cases, the knights would've fought on foot even when not knocked off their horse, since their horse might not even be on the battlefield to begin with.
Sources:
* Stephan Morillo, Warfare under the Anglo-Norman Kings 1066-1135
* Stephan Morillo, [The "Age of Cavalry" Revisited](_URL_0_)
* Jim Bradbury, Battles in England and Normandy, 1066-1154 (Part of "Anglo-Norman Warfare", edited by Matthew Strickland) | [
"Many knights during Medieval battles fought on foot. Attacks would be carried out on horseback only under favorable conditions. If the enemy infantry was equipped with polearms and fought in tight formations it was not possible to charge without heavy losses. A fairly common solution to this was for the men-at-arm... |
how is a modern minted coin ever worth more than its face value, isn't that exactly what money is a guarantee that you money will be what it says it's worth? | ....an official currency coinage is only ever worth exactly its face value.
are you thinking about those tv commercials for gold clad coins? those coins are produced by a company named National Mint or something stupid like that. those are collector scams. they're not worth anything. | [
"Coins of the United States dollar (aside from those of the earlier Continental currency) were first minted in 1792. New coins have been produced annually and they make up a valuable aspect of the United States currency system. Today, circulating coins exist in denominations of 1¢ (i.e. 1 cent or $0.01), 5¢, 10¢, 2... |
In what year and battle did the last recorded charge of knights in heavy armor occur? What conflict last saw widespread use of knights in heavy armor? | If you by "knights" mean armoured cavalry consisting solely of noblemen, then the charge of the Polish crown army consisting of mostly [Polish winged hussars](_URL_0_), although they had stopped wearing the wings at that time, in the Battle of [Kliszow 1702](_URL_1_). The Polish cavalry threw the Swedish cavalry into disorder and then charged the Swedish infantry twice, but was repulsed both times. The Swedish cavalry then attacked and drove the Poles from the field. | [
"One of the greatest distinguishing marks of the knightly class was the flying of coloured banners, to display power and to distinguish knights in battle and in tournaments. Knights are generally \"armigerous\" (bearing a coat of arms), and indeed they played an essential role in the development of heraldry. As hea... |
Another military or logistics question, how does an army pass a mountain, whether it's supposedly impassable or passable? | They (typically. Some people tried some crazy things) just went through known passes, which is why mountains are such great natural defenses. If there are only a small number of passes the defending army knows exactly where their enemy is coming through and can wait for them. Many mountain passes (esp. high mountain passes) are not very wide, either, meaning that armies could only pass through slowly and with great care. It is a pretty dangerous business.
I've been talking about the Mongols too much in this sub recently, but they were going on a raid against Russia and decided to cross the Caucasus Mountains in the middle of the winter. Unfortunately there was only one real passable spot, at Derbent. So they had to "hire" (bribe/threaten) guides, but the guides were able to run up ahead and warn everyone on the other side of the mountain that the mongols were coming for an invasion. (Genghis Khan and the Mongol War Machine By Chris Peers). Don't worry, the Mongols win and then kill everyone and terrify all of the Russian Princes for years, but the Mongols also REALLY want to find a better way to get through (they eventually just take over the city of Derbent, which makes it easier).
| [
"For the crossing of the mountains, the Army was divided into two main columns, the first, commanded by Captain General San Martín and supported by Brigadier Major Miguel Estanislao Soler and Brigadier Bernardo O'Higgins, would take the Los Patos Pass and the second, commanded by Colonel Juan Gregorio de las Heras,... |
how does a pro gamer make a living after he / she retires? | It's a bit of a tough question to answer as the pro gaming industry hasn't delivered that many retirements so far.
However, if they follow a gathering based on not just their skill, but also their personality, they could complete a full career by Twitch (subscriptions, ads, donations) and YouTube (ads, sponsorships, Patreon), even if they can no longer compete at -the- top level.
Or their knowledge on games could indeed land them a job in a gaming company.
In my opinion it can be compared to "normal" sports in this regard, as sports knowledge (- > coach, manager...) or personality (media personality) can allow you to continue your career even after retirement from actual top level competition. | [
"In Career mode, the game puts the player in responsibility of a workshop where they must complete tasks that involve modifying pre-built computers, (e.g. removing viruses, adding new parts) or outright building a brand new computer to earn in-game cash, which can be spent on purchasing brand new parts, including c... |
how do spam telemarketers make money since almost everyone just hangs up? | With VOIP and cheap offshore labor, it costs virtually nothing to make those calls - partly *because* no one answers, or hangs up immediately. If you make 10,000 calls - that's every number in an exchange - and get three or four bites, you've made money. | [
"BULLET::::- Telemarketing fraud takes a number of forms; much like mail fraud, solicitations for the sale of goods or investments which are worthless or never delivered and requests for donations to unregistered charities are not uncommon. Callers often prey upon sick, Disability and elderly persons; scams in whic... |
since inflammation in the body causes numerous fatal diseases(cancer,heart disease, etc.),why can't we just pop a few nsaids like ibuprofen every day and be on our healthy way? | Taking too many NSAIDs gives you stomach ulcers for starters. There's lots of side effects to antiinflammatories. | [
"Inflammation has many possible causes, including irritation by environmental substances, physical trauma, and infection such as bacterial, viral, or fungal. Some of these infections are sexually transmitted diseases.\n",
"Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, can cause f... |
How did the Roman people handle military defeats? | How would we know what an "average citizen" thought? Every text we have is produced by the elite class. Whether people lost friends or family is impossible to know in the specifics.
We do know that military disaster did not affect the political careers of the generals involved. Rosenstein in *Imperatores Victi* demonstrates very well that statistically military defeat had little or no impact on the further career of a general. Losing, as long as you got out alive, simply didn't matter.
On the personal level, among the elite, we do have evidence for friends and family grieving for loved ones. Both Catullus and Propertius write about that. Logically you would by extension think the "average citizen" would have similar feelings. There might be stele that can give more of a middle class view of the matter, but I don't know them and I don't have the resources to get them right now. | [
"Rome was a war-faring nation and was accustomed to setbacks. However, the recent string of defeats ending in the calamity at Arausio was alarming for all the people of Rome. The defeat left them not only with a critical shortage of manpower and lost military equipment, but also with a terrifying enemy camped on th... |
the difference between iphone and android, and the pro's and con's of each. | Things Android phones can do *without* being rooted (the same level of permission you currently have on the iPhone):
* Change the keyboard input. [8pen](_URL_1_), [SwiftKey](_URL_0_), and [Swype](_URL_9_) are some good examples.
* Use any appstore or download apps directly from web pages. The [Amazon AppStore](_URL_10_) even has one free (as in, a 100% discounted) app every day.
* Put widgets on your home screen, like the HTC clock/weather widgets, calendar widgets, [gReader](_URL_2_) widgets, and battery management/service widgets for turning on/off features like 4G, WiFi, GPS and Bluetooth.
* Explore your filesystem with apps like [ASTRO File Manager](_URL_3_).
* *Admittedly there are fewer games out for Android than iPhone* (in surveys a while back, a statistically significant percentage of people said they got an iPhone primarily for the games) but there is a great family of video game console emulators like [SNESoid](_URL_4_) for the Super NES, NESoid for the NES, and GENSoid for the Sega Genesis among others.
Things you can do *with* a rooted phone:
* Install a custom ROM (an operating system like OSX or Windows 7) like [CM7](_URL_5_).
* Underclock/overclock the processor to improve battery live or improve performance.
* Use your phone as a wireless hotspot without paying the extra $25/month for the service.
* Create comprehensive recovery files (backups) with [Clockwork Mod](_URL_6_). Additionally backup, freeze and delete apps on your phone through [Titanium Backup](_URL_7_).
No iPhone supports 4G, at least one Android phone now supports Netflix, and Android is [open source](_URL_8_).
But Steve Jobs and Apple will always be the king of "it just works." So if you want to sacrifice all/most of those features to never have to learn a phone that you'll probably be owning for the next 1 or 2 years, Apple might be the phone for you. I just wanted to enumerate all of the reasons why Android phones are for me.
If it's any credit to Apple, their products have definitely been successful at bringing space-age technology to the baby boomers. | [
"The iPhone runs an operating system known as iOS (formerly iPhone OS). It is a variant of the Darwin operating system core found in macOS. Also included is the \"Core Animation\" software component from Mac OS X v10.5 Leopard. Together with the graphics hardware (and on the iPhone 3GS, OpenGL ES 2.0), it is respon... |
Considering all types of movement we're subjected to, how fast are we actually traversing through space at any given point in time? | what is the reference point?
this question is asked all the time and it's always the same..
1. Do a search this has been asked before
2. What exactly are we calling our fixed reference point? (the entire universe is in flux)
| [
"With current technology severely limiting the velocity of space travel, however, the differences experienced in practice are minuscule: after 6 months on the International Space Station (ISS) (which orbits Earth at a speed of about 7,700 m/s) an astronaut would have aged about 0.005 seconds less than those on Eart... |
why does spain have strong, independent cultures (i.e. basque, catalonia) while other european nations seem to be more culturally and linguistically uniform? | While I don't disagree with your question, let me find you some examples which invalidate it:
- Belgium is part French part Dutch, different languages, different traditions, different cultures.
- Yugoslavia, but that was only a stable country under Tito.
- Turkey and its Kurdistan part.
- UK (or was it GB?) and Scotland and Northern-Ireland.
- The former east and west parts of Germany, still cultural very different.
- Czech and Slovakia were split up in the late 1990s IIRC.
- Italy and Sicily.
| [
"However, some traits of the Spanish spoken in Spain are exclusive to that country, and for this reason, courses of Spanish as a second language often neglect them, preferring Mexican Spanish in the United States and Canada whilst European Spanish is taught in Europe. Spanish grammar and to a lesser extent pronunci... |
why do guys insist on sending unsolicited dick pictures. does that ever really work? | Men are very visual creatures, and quick to arouse. A man can go from no arousal to immediately turned on just with a quick flash of a girl's boobs. As a result of this nature, many men don't grasp that women don't work the same way, and aren't interested much in seeing a dick unless already aroused.
Combine that with the general negative effect that arousal tends to have on your ability to make good decisions, and you have horny men sending what they think are arousing pictures to someone who is in no mood for them. | [
"\"Snuff\" follows three men who are waiting to immortalize themselves into pornography history as they wait to bed Cassie Wright, a former porn queen who has fallen into harder times. Each chapter follows a different guy (Mr. 600, Mr. 72, and Mr. 137), as well as Sheila, the female wrangler who dictates who is the... |
how did early man manage to drink the recommended 2 litres of water a day without access to clean water and remain strong enough to maintain his active lifestyle? | The recommended two litres of water a day is junk science invented by drinks manufacturers to sell more products. Actual scientists say you should drink when thirsty, and not drink when not thirsty (unless you are sick or actually dehydrated).
Clean water was difficult to find, and at first humans settled wherever they could find fresh water. Later, they learned how to dig wells, giving them access to more fresh water.
Of course, by our standards, the water wasn't exactly clean. But people had immune systems to cope: being exposed to all the common pathogens very early in life helped give people the immunity they needed.
It was still possible to pick up parasites through the water, though, so it wasn't totally safe, and infant mortality in particular was very high. But the human race compensated for that by not having birth control in those days: those that did survive childhood could usually go on to live long and relatively healthy lives (the average life expectancy of around 40 is so low because of the high infant mortality, and because of constant wars and battles).
This is where beer comes in. Beer is mentioned in Ancient Egypt, although it was quite different from modern beer. Essentially, it was liquid bread, with a much lower alcohol content than we're used to now, so it could be given to children. In mediaeval Europe it was an important supplement to a peasant's diet (the belief that beer is considered a "foodstuff" in Bavaria is a complete urban myth, but not an implausible one). The process of brewing the beer killed off most of the germs and parasites, and the alcohol killed off the rest.
Basically, a combination of humans not actually needing as much water as the Coca-Cola Corp wants you to believe, a more robust immune system, and the discovery of the brewing process. | [
"A typical person will lose minimally two to maximally four liters of water per day under ordinary conditions, and more in hot, dry, or cold weather. Four to six liters of water or other liquids are generally required each day in the wilderness to avoid dehydration and to keep the body functioning properly. The U.S... |
Does smoke have weight? | Smoke has weight, yes, but that experiment is no way to find it. For example, try it with a piece of magnesium instead of a cigarette. If you burn magnesium, it gives off some smoke, and at the end the ashes are actually **heavier** than the original piece of magnesium. How? Burning is just rapid oxidation, and what's left is magnesium oxide, which contains oxygen from the air, which has mass. Burning takes mass out of the air and adds it to the ashes and the smoke, and the proposed experiment doesn't take that into account.
Much of a cigarette burning is carbon, so when that oxidises it becomes carbon dioxide (or monoxide), both of which are gasses which dissipate away. Do they count as part of the smoke? Probably not, but they do in that experiment.
I don't know how to formulate an experiment to weigh smoke, but the experiment given in the film is flawed.
Edit: Also, because this way of thinking about fire seems so intuitively reasonable, it was pretty much our best scientific model of it for a long time. They called it [phlogiston theory](_URL_0_). | [
"Cigarette smoking for weight loss is a weight control method whereby one consumes tobacco, often in the form of cigarettes, to decrease one's appetite. The practice dates to early knowledge of nicotine as an appetite suppressant.\n",
"There is much controversy concerning whether smokers are actually thinner than... |
how do you perform cpr and give compressions to a person who has fractured his chest bones? | In a situation when a person actually needs CPR a beating heart takes precedence over anything else even a fractured sternum/ribs. if the ribs puncture your lung and give you a pneumothorax, they can still fix you up later, but if the heart stop beating only for 5 minutes your brain cells will start to become necrotic right away (with the hippocampus being the most vulnerable).
Source: took a CPR class in med school, asked the same question that was my instructor answer. | [
"BULLET::::- Cardiopulmonary Resuscitation (CPR) A series of chest compressions and ventilations that try to circulate blood containing oxygen throughout the body to vital organs in an attempt to resuscitate a victim. A lifeguard performing CPR on an adult should use two hands on the chest, with the ring finger of ... |
Why did the Japanese attack the United States to bring the US into WW2? Were they completely the aggressors or had some US policy given them reasons to attack? | For about 40 years the US and Japan had been on a collision course. A whole host of factors made it so that the nations and populations felt each other was a natural foe, and that when war came it would be particularly brutal.
To go through a few:
1. Residual Colonialism clashing with Japan's desire to make good its industrialization and ascendancy. The US and UK were still committed to the "Open Door Policy" and Western domination of Chinese and nearby markets, while Japan sought a greater sphere of influence itself after smashing Russian power in 1905, and proving itself able to be a colonial power in its own right.
2. Race based policy and rhetoric on both sides. California for instance had some particularly heavy handed anti Asian policies,a nd immigration was severely limited. And deeply held beliefs that immigrants owed allegiance to the Emperor over Washington. Meanwhile 3 generations of Japanese were fed the nationalist narrative of the Yamato Race, one people focused on greatness brought together under the Divine Emperor, and who would replace the Colonial powers as the new dominant power of the Asian peoples.
3. The feelings of dishonor and anger over the Naval Treaties. In the 20's and 30's at the Washington and London Conferences Japan was pressured into accepting a 5:5:3 ratio in Battleships and in general naval tonnage compared to the US and UK. That was seen not as a recognition of global vs regional interests, but as a move to hinder the growth of the rising sun of Japan. There was then national rage and mourning when multiple unfinished battleships were taken from the dockyards and scuttled.
4. Progressive tightening of economic screws by FDR. When Japanese officers in Manchuria repeatedly either acted without prior approval or created crisis, Japan found itself in its long awaited move to conquer China. In response FDR went through a series of restriction to prevent the US from feeding the war machine for a conflict he was against. Items such as scrap metal were not allowed to be sold to Japanese customers. Finally Oil was embargoed, and this then would have either forced an end to the war, or the IJA and IJN would have ground to a halt.
5. Prevailing thought on how to fix that weakness was to snatch up the Dutch East Indies, and Malaysia from the Netherlands and the UK. However the US controlled Philippines stood in the way, and even without a direct attack the fear was that the US would come to its allies aid, and either way a general war would commence.
So the key becomes, with a smaller navy, how do you secure the resources needed to wage war, while also fighting off an enemy fleet equal your own?
From that problem was born the plan to attack pearl Harbor and try to remove one of those considerations for a time. Thus the war would go A. Knock the USN off balance and freeze them B. Seize the resources you need to keep going in the South pacific. C. Prepare a string of Islands through the Pacific to use as bastions to bleed the USN when it did come to fight, then a giant climactic battle could be joined to sink the rest of them. D. Then hopefully the US would be tired of war and open negotiations which would leave Japan with the territory it needed to be resource independent.
Excellent Sources: War Plan Ornage by Edward S. Miller
Pacific Crucible by Ian W. Toll
and Shattered Sword by Parshall and Tully | [
"In late 1941, Japan's government, led by Prime Minister and General Hideki Tojo, decided to break the US-led embargo through force of arms. On December 7, 1941, the Imperial Japanese Navy launched a surprise attack on the American fleet at Pearl Harbor, Hawaii. This brought the US into World War II on the side of ... |
how did we figure out that burning rocks would make metal? | Metal working is *way* past caveman times.
We figured out fire, and we figured out how to make *hot* fire (which we needed to make strong pottery, which we needed for storage because we figured out agriculture which, incidentally, meant we needed to figure out writing).
A lot of this is, necessarily, speculative, but the likely scenario is someone put some metal in a hot fire and noticed it melted. Possibly people found free-lying metal deposits, or someone had rocks with a high degree of iron impurities.
A lot of stuff like this happens *by accident*, and then possibly someone *eventually* thinks of something to do with it. | [
"The traditional method of cracking rock was fire-setting, which involved heating the rock with fire to expand it. Once the rock was heated by fire it was quenched with water to break it. Fire-setting was one of the most effective rock breaking methods until 1867 when Alfred Nobel invented dynamite.\n",
"The cons... |
How did gunpowder weapons change siege tactics? | They ended up not changing the strategic nature of siege warfare that much at all, except perhaps making the defender even stronger then they had been in previous centuries (how much so varies). Siege tactics, however, changed much more - but less than you'd expect.
There was a brief period from about the late 14th century to the early 15th century in which advanced cannon (corned powder, bronze barrels, iron shot) were sufficiently new that they let badly-built castles fall quickly, but it was fairly soon after their introduction that defensive countermeasures were introduced.
But even without those countermeasures, writers of the era noted that *the defender will always bring more guns to bear*. Any castle or fortification is going to be able to outrange and outgun any attacker, as the attacker will only have so many cannon that he can bring into firing range. When you combine this with how incredibly close the attacker needs to bring his weapons to have any effect on the massive walls, this creates a situation that is hugely tilted to the defender's advantage.
Defensive tactics became concerned with overlapping fields of fire, angled walls to deflect cannon balls, and secondary defenses to fall back too. The attacker would have to fight their way up a horrific outer killzone in which any given approach would have the defender's full firepower focused on them (usually by constructing trenches and earthworks inch by inch in a process that might take weeks or months), try their best to knock out the defender's well protected guns near the section of wall they sought to breach (if they didn't, any attack would be blown to shreds), make at least three breaches in the wall, and then launch a simultaneous assault - one that was usually unsuccessful.
[A comparison of pre and post gunpowder "ideal" fortifications from David Eltis' *The Military Revolution in Sixteenth Century Europe.*](_URL_1_)
It was unsuccessful because the defender at this point would have built the famous "semi-circle" around the breach points - a massed amount of artillery, arquebusiers, musketeers, and pikemen with their weapons aimed at the small breach in the wall and ensconced safely behind cover. When the enemy troops charged in, everyone would fire. And keep firing. Once the smoke cleared, the pikemen would charge the disoriented enemy and rout them - and the process would begin again.
Even the most outdated of castles could be decently well defended in this situation, by allowing the attacker to breach the walls and killing him when he got in. Custom designed fortifications were even more impossible to take - I'd recommend reading up on the Second Siege of Rhodes and the Siege of Malta to see exactly what faced an attacker who assaulted a fortified position with a determined defender.
**Bibliography:**
Eltis, David. *The Military Revolution in Sixteenth Century Europe.* New York: I.B. Tauris Publishers, 1998. Print.
Hall, Bert. *Weapons & Warfare in Renaissance Europe.* London: The Johns Hopkins Press Ltd., 1997. Print.
**Other comments:**
> It's my understanding that cannons were around before handheld gunpowder weapons, and were used in Europe as far back as the 1300s, so I'm hoping there must be some examples of sieges using these weapons.
A common opinion, but it's actually unclear. The current historiography has "handheld" (two man) weapons as the first to emerge, which makes sense when you think of how complicated it is to cast the barrel for/successfully use large gunpowder weapons.
> On a related note, I'm also interested in learning about military strategy and tactics from the introduction of gunpowder weapons up until the 1800s, so are there any books or other resources that would help me out? I'm looking for a fairly general overview of how gunpowder changed warfare, especially in Europe, and while I appreciate that this is a very big field I'm quite keen to learn about it, so any books or other resources would be a great help.
Ha, I came to this subreddit with almost the exact same question about 8 months ago. After I had learned a lot about the subject, [I answered my own question here] (_URL_0_) along with some other ones that I had. You might be interested. | [
"The introduction of gunpowder affected the conduct of war significantly. Though employed by the English as early as the Battle of Crécy in 1346, firearms initially had little effect in the field of battle. It was through the use of cannons as siege weapons that major change was brought about; the new methods would... |
Palestine to Israel | Do you mean, why did the State of Israel call itself “Israel” and not “Palestine”? The end of the British mandate on 14 May coincided precisely with the declaration of the State of Israel, which was made that evening. A few minutes later the United States recognized Israel. Recognition from other countries would arrive in the coming hours and days.
Other than that I’m not sure I understand the question? | [
"The League of Nations assigned Palestine as a mandate to the UK in 1920. The British tried, but failed to stop large-scale Jewish immigration into the mandate. Britain returned it to UN control in 1947 and the UN divided Palestine into a Jewish state and an Arab state. Israel came into existence on May 14, 1948, f... |
If measurement causes the wavefunction to collapse, and everything is constantly interacting with everything else in the universe via gravity, why haven't all wavefunctions collapsed all the time? | Crudely, wavefunction collapse means the following. You allow your quantum system S to interact with a set of degrees of freedom M. The interaction entangles the state of S with the state of M, so that the probability distribution of some observable OS of S are correlated with observable OM of M. But perhaps you don't care about OM and only want the marginal distribution for OS. Averaging over OM produces an effective collapse: the probabilities governing future behavior of S now behave as though, at the time of interaction with M, OS took various values with probability set by the Born rule. This is what you would expect from classical probability theory, but differs from quantum mechanics because it eliminates the effects of interference between quantum mechanical amplitudes.
So, you might think that everything is interacting with gravity, and we don't care about the state of the gravitational field, so why doesn't averaging over it classicalize all probabilities? The reason is that gravity is weak: interactions with gravitons are rare. The quantum systems we look at are affected by gravity in the sense that their motion is influenced by the background gravitational field, but they are very unlikely to change the state of that field by entangling with a graviton. | [
"The measurement problem in quantum mechanics is the problem of how (or \"whether\") wave function collapse occurs. The inability to observe such a collapse directly has given rise to different interpretations of quantum mechanics and poses a key set of questions that each interpretation must answer.\n",
"The clu... |
glass is not biodegradable, and will perhaps take even longer to decompose than plastic. why isn't it made out to be as big of an issue as plastic? | I believe that the answer lies in the fact that, if you crush up glass to extremely fine fragments, it is essentially sand. Plastic, as it breaks down, continues to float, pollute, and also mimics small water-borne organisms that larger organisms feed upon. Broken glass (sand) sinks, and essentially returns to the lifecycle of a rock. | [
"This composition of bioactive glass is comparatively soft in comparison to other glasses. It can be machined, preferably with diamond tools, or ground to powder. Bioglass has to be stored in a dry environment, as it readily absorbs moisture and reacts with it. Bioglass 45S5 is the first formulation of an artificia... |
Why was Australia not fought over the same way as Africa? | > It just changed hands once(between European powers), and rather peacefully, correct?
It never changed hands between European powers. The Dutch, who were the first Europeans to map Australia, never claimed it. They mapped it and named it (New Holland), but nothing more than that. The first – and only – European power to make any claim to the continent of Australia was England.
And, the reason the Dutch didn’t make a claim to Australia was because the part they saw – the western and north-western coast – was mostly uninhabitable. The north-west portion of the continent is mostly arid land or desert. There was no benefit to be seen in this land. The logs of the ship *Duyfken* [described what they saw in 1606](_URL_0_):
> for the greatest part desert, but in some places inhabited by wild, cruel, black savages, by whom some of the crew were murdered, for which reason they could not learn anything of the land or waters as had been desired of them.
The captain of that ship [also wrote](_URL_5_):
> “... that vast regions were for the greater part uncultivated, and certain parts inhabited by savage, cruel black barbarians who slew some of our sailors, so that no information was obtained touching the exact situation of the country and regarding the commodities obtainable and in demand there.... “ He found the land to be swampy and infertile, forcing them eventually to give up and return to Bantam due to their lack of “... provisions and other necessaries ....”
It wasn’t an attractive land!
It was only much later, when Captain James Cook mapped the *east* coast of Australia, that Europeans learned that this mysterious southern land had fertile areas.
The first European claim to Australia was made on 7th February 1788, when the officers of the recently arrived First Fleet read out the King’s documents, announcing his claim to the land of “New South Wales” – but only as far west as [longitude of 135°E](_URL_4_) (this was later revised to [longitude 129°E](_URL_2_), where the current border of Western Australia is). The reason for not claiming the whole southern continent was not because the Dutch had claimed the western portion - they hadn’t - but to prevent offending the Dutch in case they *wanted* to claim that portion. However, in 1829, the British started a settlement on the west coast of Australia with no protest from the Dutch – obviously they’d worked out by then that the Dutch really didn’t want the place.
The race to settle and claim the continent of Australia over the next century was not between the British and the Dutch – the British saw their rivals as the French, who were expanding their holdings in the Pacific.
In 1803, Governor King wrote to an official in the office of the British Admiralty that:
> It was reported to me soon after the French Ships sailed that a principal object of their voyage was to fix on a Place at Van Diemens Land for a Settlement [...] with this Information I considered it my duty to establish His Majesty’s Right to that Island being within the limits of this Territory [New South Wales], I therefore despatched a Colonial Vessel [which made] an accurate Survey of King’s Island and Port Phillip at the West entrance of Basses Straits.
> Making the French Commodore acquainted with my intentions of Settling Van Dieman’s Land, was all I sought by this Voyage
> Under all these circumstances I judged it expedient to form a Settlement at Risdon Cove in the River Derwent [modern-day Hobart]
> My reasons for making this Settlement are :– the necessity there appears of preventing the French gaining a footing on the East side of these Islands [etc]
At the time, [Britain was officially at war with France]( _URL_1_).
The expedition King mentions was led by Captain David Collins of the *Calcutta*. He did start [a settlement in Port Phillip in 1803]( _URL_3_), in order to prevent the French from using the area as a base for military actions. However, he abandoned the settlement after only eight months, due to conflict with the local Aboriginals, and poor outlook for farming. He moved on to the Derwent River, where he founded Hobart Town.
Nearly a hundred years later, the French were still seen as a threat by Australians. The threat of French military action in the Pacific in the late 1800s was one of the many motivations for federating the colonies into a single country.
However, there was never a war over Australia, nor did it ever change hands from one European power to another. As to why not... that’s a mystery. People didn’t write down their motives for not starting a war which didn’t happen. However, I can speculate:
* The Dutch saw no reason to go to war over a continent which they knew about 150 years before the English, but which they’d never bothered to claim because it was inhospitable.
* France, the other major player, was too busy with revolutions and defensive wars in Europe in the late 1700s and early 1800s to take action in the Pacific arena on the other side of the world. They did posture a lot, and did claim many islands in the Pacific near Australia, but never actually moved on the colonies themselves.
| [
"Both the New Zealand and South African teams had toured Europe in 1905 and 1906 respectively, both achieving unexpected but deserved success against club and international opposition. Despite the success of these two touring teams, Australia suffered poor press and with only a single win after the teams' first twe... |
what is net nuetrality? what is being for it? against it? do we have it? trying ti get it? | John Oliver made a video a few years back and one weeks ago that touches on the subject well. Basically with net neutrality, everybody's internet speed gets treated equally regardless of what websites, browsers, etc. you use. | [
"Network neutrality (also net neutrality, Internet neutrality, or net equality) is the principle that Internet service providers and governments should treat all data on the Internet equally, not discriminating or charging differentially by user, content, site, platform, application, type of attached equipment, or ... |
If autonomous cars become the norm, how much time and gas would we save on a typical weekly commute? | I can't answer our question, but I can add some more sources of waste that would be eliminated by self-driving cars.
In theory, you would not longer need to stop at intersections. The computer algorithm could very quickly work out a way to get everyone through [with nobody stopping](_URL_0_).
In cases where the roadways are clear, there would be no traffic. The cars could communicate and get out of each-others' way so that none of them would need to brake or swerve unexpectedly.
The fuel costs of sitting at lights and sitting in traffic would be effectively eliminated. | [
"Manually driven vehicles are reported to be used only 4–5% of the time, and being parked and unused for the remaining 95–96% of the time. Autonomous vehicles could, on the other hand, be used continuously after it has reached its destination. This could dramatically reduce the need for parking space. For example, ... |
considering how contagious vomiting bugs are like norovirus, why aren’t we always sick with them? | Most extreme pathogens are caught early by food manufacturers. All of them are required to have up to date HACCP plans, food safety plans, and as of 2018 putting more emphasis on CoA of raw materials and doing due diligence on them. Check out the recalls. Almost all of these are 100% voluntary and require a lot effort and oversight. Look at blue bell. They got hit with listeria twice and after 8 years they are only just now coming back to the size they once were.
_URL_0_
Basic fact is that food companies, most of the time, catch these nasties before you get them. Of course norovirus is special because a sick worker at a tacobell wont take time off and then everything they look at is contaminated. Its rare that this happens and only spreads so far before everyone is healed. Also the immunity of norovirus varies from person to person but is usually a short amount of time. | [
"Noroviruses are transmitted directly from person to person (62–84% of all reported outbreaks) and indirectly via contaminated water and food. They are extremely contagious, and fewer than twenty virus particles can cause an infection (some research suggests as few as five). Transmission can be aerosolized when tho... |
why are credit cards and credit so important? what's wrong with just a debt card? | Debit cards are fine, you just don't build credit with them. You're using cash you actually have in an account, as opposed to using a credit line.
Credit is important because at some point in life, you will invariably need money you don't have. For example, you may need to take out a loan for a house, finance a car, etc. If you're doing business in an individual capacity or as the representative of a company, it also helps to have a good credit score for much the same reason. A bank is more likely to lend to a business if its guarantors have good credit.
For my part, I think it's advisable to build credit to a point where you can shred the cards and go cash-only in like in ye olden tymes. I've read studies saying you spend (waste) less money that way, and nothing's quite as baller as paying for everything in bills like a prohibition-era gangster. | [
"Declines in credit card debt are often misinterpreted because they fail to include information about charge-offs. The possible causes for a decline in credit card debt are consumers paying down their debt, credit card companies writing charged-off debt off their books, or a combination of the two. Inclusion of cha... |
Does pollen carry or assist the spread of illness? | Pollen can act as a significant vector for viruses (_URL_0_ you can only see the abstract, but that's enough to know that pollen is a viral vector), however pollen doesn't actually increase the amount of pathogenic particles leaving someone with a transferable disease unless they are allergic. | [
"The pollen which causes hay fever varies from person to person and from region to region; generally speaking, the tiny, hardly visible pollens of wind-pollinated plants are the predominant cause. Pollens of insect-pollinated plants are too large to remain airborne and pose no risk.\n",
"Dunbar devised techniques... |
How did scientists recreate the 1918 Influenza Virus? | Scientists were able to determine the genetic sequence of the 1918 virus using samples from a woman who had died of the virus and was buried in permafrost. Then, they used the sequence to rebuild the virus, likely by expressing the genome within a cell, which would produce viral proteins that assembled into infectious viruses. This was done in 2005 by the CDC. The primary goal of recreating this virus is to study what made it more deadly than current viruses, as well as what made it a pandemic. There is also a hypothesis that it is safer to work with, because it has similarities to the H1N1 virus that many people were exposed to or inoculated against in 2009, and thus would not act like a pandemic flu if it were released accidentally. Hopefully, this is never tested and remains a hypothesis. | [
"In early 2004, David Lipman, Lone Simonsen, Steven Salzberg, and a consortium of other scientists wrote a proposal to begin sequencing large numbers of influenza viruses at The Institute for Genomic Research (TIGR). Prior to this project, only a handful of flu genomes were publicly available. Their proposal was ap... |
what does hydrogen peroxide do to earwax chemically that makes it easier to remove? | It doesn't do anything chemically to the earwax, other than possibly diluting it. It works mechanically. The bubbles help loosen the wax. The bubbles are caused by an enzyme called catalase that exists in the dead skin cells in the wax. This enzyme rapidly breaks down the hydrogen peroxide, releasing bubbles of oxygen. | [
"Hydrogen peroxide - urea is mainly used as a disinfecting and bleaching agent in cosmetics and pharmaceuticals. As a drug, this compound is used in some preparations for the whitening of teeth. It is also used to relieve minor inflammation of gums, oral mucosal surfaces and lips including canker sores and dental i... |
growing plants indoors with non-solar light...help understanding plant needs / physics | Hahaha, c'mon man, just say it. "I'm growing pot, help plz?"
Even if you aren't though, you might just want to go to /r/trees and ask for growing tips. Same function really. | [
"When planning an indoor garden it is important to choose plants with light requirements that are conducive in homes. To maximize a plants sun exposure, place it in a room that receives high amounts of natural light. Artificial lights are an alternative if the natural lighting in a room is insufficient, and they ca... |
flight, how does it work? | Ever stuck your hand out a car window and tilted it? You feel a force pushing your hand up or down, this is Lift. Lift counteracts Weight from gravity and enables flight.
While the shape of the wing provides some lift, the majority of it comes from the angle that the wing is going into the wind at (angle of attack). If you want to go up then you tilt the nose up, if you want to go down you tilt the nose down just like angling your hand out the car window.
But tilting your hand also creates a force which pushes it backwards, this is called Drag. To counteract drag you need Thrust which we get from engines that drive propellers or giant fans(jet engines).
And those are the four basic forces of flight - Lift, Weight, Drag, and Thrust. If you've got enough Lift to overcome your Weight then you can fly but it generally takes high speed to generate that lift so you need enough Thrust to overcome the Drag. | [
"Flight is the process by which an object moves through an atmosphere (or beyond it, as in the case of spaceflight) without contact with the surface. This can be achieved by generating aerodynamic lift associated with propulsive thrust, aerostatically using buoyancy, or by ballistic movement.\n",
"Flight is the p... |
how does fat and energy work? how is it that you burn fat by exercising, but you can have fat and still be out of energy. if i just stop eating, why isn't it that i can be full of energy until my body is out of fat? | This will be a little complicated.
Fat is energy, but it's not immediately usable as energy; since cells are the smallest living unit, fat has to be broken down into parts that the cells can use before it is actually usable. Of course, breaking down molecules takes time, as well.
Breaking down the fat releases the usable parts (glucose) into the bloodstream. Your body automatically tries to keep the blood glucose level steady. Why? Because too much blood glucose is inefficient; too little blood glucose is dangerous.
So when you exercise, you are using up blood glucose. Once the level gets too low, your body will start breaking things down to bring the levels back up. It starts with carbohydrates, because those are easily broken down into glucose. Once those are almost gone, then it starts breaking down the fats. If the fats are running out, then it will turn to proteins and muscle. Light exercise will burn up the carbohydrates. Strenuous or extended exercise will start burning up fats. Flight-or-fight, life-or-death situations will most likely cut into your muscles and proteins.
Because of this order of energy consumption, your body doesn't like to use too much energy. It doesn't like to start burning up fat, because that is the "reserve" energy that the body can use before it goes into full panic mode (burning muscle).
So when you exercise a lot, your body will grudgingly start breaking up fat. That's why you have to do a lot of strenuous exercise to lose fat; you have to force the body to use its reserve energy.
The other side of this coin is energy storage. After a meal, when your blood is full of glucose, your body will start storing the energy away for a rainy day. Your body will start turning the extra blood glucose into fats, and storing those fats away for later use. That's why you don't have a huge burst of energy after a meal; all that extra glucose that you are digesting is being turned into fats. | [
"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",
"The body's primary source of energy is glucose;... |
how does accutane exactly work, what does it do with the body system, and why do results vary from person to person? | The Accutane molecule is similar in shape to Vitamin A. It stops sebaceous glands from working. Think of it as turning off the faucet that pumps the gunk into the acne. It doesn't work for everyone because it doesn't work for every time of acne. It works best for the big nodular acne, because that is mostly caused by overproduction from sebaceous glands. Other types of acne have different causes.
I don't quite understand what you mean by it affecting the body system.
I hope this helps. | [
"The substance acts on mucus membranes, restoring the physiological clearance mechanisms of the respiratory tract (which play an important role in the body’s natural defence mechanisms) through several mechanisms, including breaking up phlegm, stimulating mucus production, and stimulating synthesis and release of s... |
What really happened in melee combat? | It really varies wildly based on culture, time, technology, organization, numbers, etc. Despite being from a post-gunpowder era, I feel you might be interested in a clash of pikes.
Drawing from my study, the early 16th century, if serious combat was joined it was likely to be a clash of equally matched pike formations. If one side had a serious advantage due to flanking, supporting gunfire, or other factors then the combat was likely to end quickly in a rout or retreat (or massacre). Otherwise, you'd have the famous "bad war" or "push of pike".
While one side might brace to receive a charge, it was more common for both to charge as soon as they were close enough to try and gain an advantage in the ensuing melee. The two formations would slam together, and pikes would pierce people and throw them to the ground. The armored front ranks might fare surprisingly well, but the pikes would reach back to the greener troops behind the first few ranks who would have less complete suits of plate and slice into their flesh. The formations would push and shove against each other in a horrid mass of pikes, men, and mud as the earth beneath their feet stirred into dust. Soldiers further back would try and drag their wounded friends away from the melee, and humanely dispatch mortally wounded enemies with a quick thrust of a sidearm (dagger or sword), but there was serious risk of being trampled to death if wounded.
Additional pike formations might join the clash or create others nearby, but eventually enough time would pass that auxiliary infantry would be able to join, or they might have already been attached to the formation. These are dedicated troops that are meant to turn the tide in a push of pike, and whichever formation had included more of them would have a serious advantage. Soldiers of the Holy Roman Empire might bring along two-handed swordsmen, who would try to hack their way into the enemy formation or (maybe) cut the enemy's pikes into pieces. The Swiss would have their halberdiers join their pikemen in pushing, but the halberds could be drawn backwards and forwards to saw through armor and into men's bodies. The Spanish would send fighter in plate armor, steel shields, and nimble swords to slip past/under/to the side of enemy pikes and stab at the men in the formation - even sliding/wriggling over the ground if it was muddy enough.
This screaming, cursing, struggling mass of men would continue shoving against each other until one side had enough and fled, often dropping their pikes in the process, or disengaged and retreated. This could be caused by flank attacks by cavalry or other infantry, the soldiers suffering too much psychological trauma to go on, or point blank arquebus and/or crossbow fire breaking their cohesion. Officers would seek to prevent this by quickly directing troops to gaps, keeping an eye out for flankers or missile troops, and rallying the troops to keep fighting.
During these battles, small units of arquebusiers or crossbowmen would often be intermingled with the formation and fire point blank into the enemy's faces. In the Battle of Ceresole, the French included an entire line of arquebusiers right behind the first rank of Swiss pikemen. They caused a dreadful slaughter among the opposing Landschneckt, but must have not enjoyed it when the lines met. Regardless, bullets and crossbow bolts would be flying into the front ranks and flanks, who would trust to luck and their armor to deflect the worst of the damage.
You can see how critical morale would be in this kind of warfare - a single man dropping his pike and fleeing could be enough to start a rout. "Bad war" was deeply feared by all soldiers, and pike formations tried their best to ensure that the clash was on terms that was very favorable to them - but the realities of combat meant that matched encounters of pikes occurred in most major battles. | [
"Melee combat is split into two phases. In the first phase, the player approaches an enemy and attempts to punch them, as with most beat 'em up games. If the player successfully hits the enemy, the game enters attack mode. If the player misses and is instead attacked themselves, the game enters defense mode. Both m... |
What burns during re-entry? | There is not burning from reentry, but heat to the point where the air becomes ionized and a plasma, and the material is red hot and begins to vaporize.
What is occurring is shock heating, or heat due to change in pressure. It is known that when a gas expands, it cools, and in the same way, when it is compressed it heats up.
On several miles a second projectiles, the pressure will be so extreme that temperatures reach thousands of degrees. | [
"The most important first action is to stop the burning process. The source of the burn should promptly be removed (or the patient removed from the source). If the person is on fire, he/she must be told to stop, drop and roll, or extinguish the fire by covering them with heavy blanket, wool, coat, or rug. Burning c... |
how are there different "types" of spicy sensations from eating spicy food? | Because there are different compounds interacting with different receptors.
Peppers have capsaicin, which triggers the same receptors as hot temperature receptors.
Wasabi and mustards have isothiocyanates, a different compound. They are also short lived due to not being oily and volatile, meaning they can easily be washed away, or they evaporate away. | [
"Gustatory sweating refers to thermal sweating induced by the ingestion of food. The increase in metabolism caused by ingestion raises body temperature, leading to thermal sweating. Hot and spicy foods also leads to mild gustatory sweating in the face, scalp and neck: capsaicin (the compound that makes spicy food t... |
How is it that humans can learn vocal language to virtually perfect speech yet still be illiterate? | Most of this is because the mapping of symbols on the page to sounds is arbitrary. When speaking you're mapping sounds to meaning. This is something you brain has specifically evolved to handle.
For written text we've invented some arbitrary symbols, we've decided that they map to specific phonemes (or they map in a context dependant manner). Mapping shapes on a page to sounds/words and then mapping that to meaning is something you specifically have to learn. It's an additional skill above and beyond learning to speak a language and you need to learn it. I can speak a number of things in Thai and Korean but I literally have no idea what those things look like on the page nor have any understanding of what sounds their lettering represents.
Alongside this many, many people have dyslexia or related issues with written comprehension which make learning to read non-trivial for them.
| [
"One of the fundamental problems in the study of speech is how to deal with noise. This is shown by the difficulty in recognizing human speech that computer recognition systems have. While they can do well at recognizing speech if trained on a specific speaker's voice and under quiet conditions, these systems often... |
how do furnaces work? | fire from natural gas (or whatever the gas source is) being pushed through the vents via a blower fan | [
"An industrial furnace is an equipment used to provide heat for a process or can serve as reactor which provides heats of reaction. Furnace designs vary as to its function, heating duty, type of fuel and method of introducing combustion air.\n",
"The furnace is initially loaded with the material to be fused, whic... |
Would it be possible for Jupiter and/or Saturn to ignite? | If you did mean set on fire as in a spark causing the hyrdrogen to ignite, no. Oxygen is required for hydrogen to combust, and the composition of Jupiter as far as we're aware contains only a very small amount oxygen.
Also although not a very scientific approach, considering that it's 4.5billion years old now, if it were possible for it to spontaneously combust it probably would have done by now anyway. | [
"BULLET::::- In the anime \"Heroic Age\", Jupiter is destroyed when a high-powered energy gun is used to knock the moon Io out of orbit. Io plummets into the atmosphere and ignites it, and intervention by the Silver and Bronze fleets leads to a cataclysmic explosion.\n",
"BULLET::::- \"Heroic Age\" (2007), anime.... |
steam trading cards, gems, mystery cards, etc... | **Steam Trading Cards are virtual cards earned by playing games on Steam. Sets of cards can be turned into game badges and tradable Steam community items.**
**Once you’ve collected a set of cards you can craft them into a game badge. Like the current badges, they are tied to your account and are shown on your profile. Unlike the current badges, crafting game badges earns you marketable items like emoticons, profile backgrounds, and coupons.**
**Level up your badge by collecting the set again and earning more items.**
**All badges now have XP which contributes to your Steam Level, a summary of your badge collection. You can view someone’s Steam Level by hovering over their avatar. Leveling up earns you non-tradable items like profile showcases, extra friends list slots, and more.** | [
"Steam Trading Cards are a digital commodity issued by Valve Corporation for use on its digital distribution platform, Steam. Steam Trading Cards are a non-physical analogue of conventional trading cards, which are periodically granted to Steam users for playing games, fulfilling tasks, or by random chance. Cards c... |
how is your normal facial expression decided? | Genetics, Stressers and muscle memory.
Genes is the first thing, you can't change these this can cause things from your skin, your face shape and where fat wants to reside.
Stressers like age, sun damage and sleep deprivations as well as allergic reactions affect the look of your face beyond genetics.
And muscle memory affects your expression based off of how your face usually is, doing it's best to give them impression the majority of the time. Usually people have a resting face that is mostly expressionless, but it might have a hint of excitement or a hint of disgust for example that gives the impression of a happy person or a "Resting Bitchy Face". It doesn't recessarily mean if you're angry all the time you will get an angry resting face, it just means that facial expressions can overtime affect your resting face. | [
"Facial expressions are vital to social communication between humans. They are caused by the movement of muscles that connect to the skin and fascia in the face. These muscles move the skin, creating lines and folds and causing the movement of facial features, such as the mouth and eyebrows. These muscles develop f... |
How much of their forces did germany devote to the eastern front in WWI? | By February 1916 the Germans had c. 50 divisions on the eastern front; by September of that year, the number had risen to c. 70 divisions. When the Treaty of Brest-Litovsk was signed, there were 1.5 million German troops in the East, of which 500 000 were shifted to the Western Front by the spring of 1918, starting already in late 1917. | [
"On the Eastern Front the volunteers and conscripts in the \"Ostlegionen\" comprised a fighting force equivalent of 30 German divisions by the end of 1943. By mid-1944 upwards of 600,000 troops of the Eastern Legions/Troops were assembled under the command of General Ernst-August Köstring, stemming mostly from the ... |
hypodermic needle model. | The magic bullet theory is that for the every person in the world when effected by a specific message will have a specific reaction.
The general concept was that if a person was presented with advertising or propaganda they would react in a specific way as a passive participant in the process, being immediately effected by the information. Or your message is fired like a magic bullet into the person brain.
The theory is generally considered disproved by studies of election results which showed the marketing and propaganda effect different audience and groups differently even though the marketing was the same. People who were subject to propaganda were often not effected by the material and were more effect by the attitude of their social group when choosing who to vote for. | [
"The hypodermic needle model (known as the hypodermic-syringe model, transmission-belt model, or magic bullet theory) is a model of communication suggesting that an intended message is directly received and wholly accepted by the receiver. The model was originally rooted in 1930s behaviorism and largely considered ... |
[Human Body] Is it possible to feel pain that is not actually there? | Yes. The simplest example would be phantom limb syndrome. There are no nerves to stimulate in this situation. Phantom limb is considered neuropathic pain, but we still don't quite fully understand the mechanism behind it.
Beyond that there are disorders that can lead to allodynia. This is when you experience pain from normally non-noxious stimuli such as a breeze. It is thought to be due to a central process in the brain. Allodynia is most notably implicated in migraines and fibromylagia. | [
"Pain is an aversive sensation and feeling associated with actual, or potential, tissue damage. It is widely accepted by a broad spectrum of scientists and philosophers that non-human animals can perceive pain, including pain in amphibians.\n",
"There are two main types of pain that we experience in our bodies: p... |
why do some things need 4 aaa batteries instead of fewer number of a stronger battery? example: why use 4 aaa when one might be able to use 2aa. | AA are not "stronger" than AAA, they just have more power reserve.
They both put out the same voltage though AA can probably do so at a higher amperage if required.
By arranging the batteries in different combinations of parallel and series you can get different combinations of "power" (voltage) or battery life (mAh). | [
"AAA batteries are most often used in small electronic devices, such as TV remote controls, MP3 players and digital cameras. Devices that require the same voltage, but have a higher current draw, are often designed to use larger batteries such as the AA battery type. AA batteries have about three times the capacity... |
Would a black hole really appear as a sphere like in Interstellar? | The science advisor for interstellar was Kip Thorne, who just shared the Nobel Prize in Physics for his modelling of the gravitational waveform emitted by two merging black holes. He had the movie studio run a relativistic ray tracing code to generate the images of the black hole (given a small accretion disk in place around it). The simulation was the most detailed of its type ever made, and resulted in the publication of 2 academic papers. It did not include magneto-hydrodynamic modelling of the material in the disc, and left out some effects such as doppler boosting, doppler shifting, and gravitational redshifting, but the Einstein ring around the black hole is entirely a result of the light travel paths around the black hole in accordance with GR.
So yes! | [
"For non-rotating black holes, the photon sphere is a sphere of radius 3/2 \"r\". There are no stable free fall orbits that exist within or cross the photon sphere. Any free fall orbit that crosses it from the outside spirals into the black hole. Any orbit that crosses it from the inside escapes to infinity or fall... |
Would I move in opposite direction in space if I pushed smaller object then me ? | Yes. If you give the bowling ball momentum in one direction, you will have the same momentum in the opposite direction. This is the same principle that allows rockets to work: exhaust goes in one direction, rocket goes in the other. | [
"Since the object's velocity vector is constantly changing direction, the moving object is undergoing acceleration by a centripetal force in the direction of the center of rotation. Without this acceleration, the object would move in a straight line, according to Newton's laws of motion.\n",
"In physics, action a... |
Historically speaking, Ukraine wasn't where it is now. It's in what used to belong to Crimea. What's the logic behind Ukraine's placement after the fall of the USSR? | I'm no expert so I don't have any answer, but could you clarify what you're talking about a little? If I look at some easy-to-find sources (wikipedia, etc.) on the history of Ukraine, I'm not seeing anything that looks like this:
> Ukraine was in a completely different part of Europe than we think of today (That is to say, more towards central-eastern Europe)
Borders have changed a bit of course, but everything I saw seemed to be situated around the western/central regions of modern Ukraine. Maybe you have a map illustrating what you mean?
This might just be me not finding good sources, of course - I've not spent so long looking, and most searches for "historical Ukraine" and the like are just full of information about historical sites within Ukraine... | [
"From 1922 until 1991, \"Ukraine\" (also \"the Ukraine\") was the name of the territory of the Ukrainian Soviet Socialist Republic (Украї́нська Радя́нська Соціалісти́чна Респу́бліка, \"Ukrayins'ka Radyans'ka Sotsialistychna Respublika\") within the Soviet Union (annexed by Germany as Reichskommissariat Ukraine duri... |
how do cameras focus, and why does the background get blurry? | This will work better if you're nearsighted, but should work even if you're not. Look at something in the distance that's blurry because it's far away. Now squint--see how, for a little moment, it's easier to see because you're squinting? Cameras essentially focus by 'squinting' -- adjusting the lens so that the focus is on something different. | [
"Photographs taken with this technique are characterized by blurred streaks emanating from the center of the photograph. The effect is nearly identical to a motion blur image in which the camera is traveling towards the subject. For this reason the zoom burst is typically used to create an impression of motion towa... |
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