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What is probability and how does it work? How are the final states of a system in superposition collapsed into one state and not another? | Truly random events don't *have* causes; that's what it means to be random. So there's no way to answer how or why; "it just does" is literally the best explanation possible.
And you can manipulate probabilities in the sense that you can manipulate the wavefunction of your system, and the wavefunction describes the probabilities of certain observations. You can't do anything like "make this event which has probability 1/(large number) happen". | [
"BULLET::::- A highly controversial view is that in such a case the arrow of time will reverse. The quantum fluctuations—which in the meantime have evolved into galaxies and stars—will be in superposition in such a way that the whole process described above is reversed—i.e., the fluctuations are erased by destructi... |
what does the 'soap opera viewing' setting look like and why does it exist if evryone hates it? | It gives movement a weird look because the tvs processor makes up missing frames in the video. Movies and some shows are shot 24fps and a lot of tvs try to air 30fps. | [
"Many complain that the soap opera effect ruins the theatrical look of cinematic works, by making it appear as if the viewer is either on set or watching a behind the scenes featurette. For this reason, almost all manufacturers have built in an option to turn the feature off or lower the effect strength.\n",
"In ... |
the current economic downturn in the middle east. | Countries in the middle east tend to be dependent upon revenue from a single resource to power their economy - either oil or tourism. Because they are so simple, economies like that are strongly tied to the resource they are dependent on. When that resource does well their economy does well, when that resource does poorly their economy does poorly.
Oil is currently down 70% from where it was a few years ago, so countries dependent upon that are suffering. The only difference between the situation in Saudi Arabia and Venezuela, for example, is that Saudi Arabia has a huge amount of cash that its saved up over the years and which it is now able to draw on to mitigate the effects of low oil prices.
Tourism to the middle east is also down sharply because there have been a series of high profile terrorist attacks on foreign tourists over the past few years. Countries like Egypt are almost entirely dependent upon tourism, and so they are similarly suffering. The only reason that Egypt isn't in a much worse position is because its been getting loans and foreign aid from the west that have helped to keep it afloat. | [
"For many Middle Eastern countries politics is heavily integrated into economic policy and has proved to be a major obstacle to effective economic reform. Instability in the region deters foreign investment and global economic integration. Political transparency has also proven to be a deterrence to economic develo... |
what kind of molecules are in everyday objects? | molecules aren't in everyday object. they ARE everyday objects. the air you breathe is made up of nitrogen molecules, oxygen molecules, co2 molecules. the water you drink, the food you eat, the chair you sit on, the clothes you wear. | [
"Molecules as components of matter are common in organic substances (and therefore biochemistry). They also make up most of the oceans and atmosphere. However, the majority of familiar solid substances on Earth, including most of the minerals that make up the crust, mantle, and core of the Earth, contain many chemi... |
what's the difference between shoe types? | There a many levels of classification. If you're looking for more "high-level" classifications then:
Dress Shoes (e.g. Blucher, Balmoral, Oxford)
Loafers (e.g. penny loafer, camp moc, boat shoe)
Boots (e.g. Work Boot, Chukka, Chelsea)
Casual shoes (e.g. Sneakers, Espadrille)
Athletic shoes (e.g. Trainers, basketball shoes, running shoes)
The difference between sneakers and trainers is fuzzy. Generally, trainers are specifically meant to be worn during sports or exercise, while sneakers are casual, canvas shoes meant for casual wear but also sometimes used for sports or exercise, and often taking inspiration from shoes developed for sports or exercise. Complicated I know.
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"Attributes of an athletic shoe include a flexible sole, appropriate tread for the function, and ability to absorb impact. As the industry and designs have expanded, the term \"athletic shoes\" is based more on the design of the bottom of the shoe than the aesthetics of the top of the shoe. Today's designs include ... |
How do you "make" color? | Paint gets its color from pigments, i.e. colored stuff. When you say something has a certain color it means it's absorbing light of some color and turning it to heat, or re-emitting it but with a different color. The light absorbed is the 'complementary' color to the color you see, since ordinary light is white and has all wavelengths of light (colors) in it. For instance, if something appears yellow, it's because it absorbs blue light, since blue is the complementary color to yellow.
The reason why stuff appears colored, then, is because things don't absorb or reflect light equally at all wavelengths. The reasons for that, in turn, are pretty complicated. It depends on the chemical composition (what elements and molecules make up the stuff) but also how the molecules are organized in the material, and how the material is composed at the larger scale. E.g. a single salt crystal is translucent, but granular salt is white - because it's broken up into many crystals with many surfaces, each of which reflects some light.
Corundum is a mineral made of aluminum oxide - a translucent substance that covers just about all the aluminum you've ever seen (aluminum forms a thin oxide layer instantly on contact with air). But just the slightest impurities in the corundum of various metal atoms will change its color. If it has traces of chromium, it'll be red and that's what you call a ruby. If it has some titanium as well, it's a sapphire. The fact that these are small (less than 1%) impurities tells you something about how subtle these things can be.
Single molecules can have a color as well, at least if you have a well-defined set of surroundings (now that I've established the surroundings are important). So for instance you can say that various compounds have various colors when dissolved in water. But you can't _quite_ say that the molecule _itself_ has that color. It may very well have a different color as a gas or solid, for instance.
Even isotopes - atomic nuclei of the same element but different mass, can have an effect on color. Which is rather impressive, since it has almost no measurable effects on chemistry in general. For instance, pure water is (very weakly) blue in color. But heavy water (where hydrogen atoms are changed for heavier deuterium ones) is colorless.
So in short, many many things can cause color. | [
"A colourant/colour additive (British spelling) or colorant/color additive (American spelling) is a substance that is added or applied in order to change the colour of a material or surface. Colourants can be used for many purposes including printing, painting, and for colouring many types of materials such as food... |
what are current active research areas in mathematics? and what are their eli5 explanations? | Math is a huge subject, but here are a few. If you want to know more, look up the Millenium Prize problems, and if you want to read a book about the various objects that mathematicians study, a good book is Mathematics: Its Methods, Content, and Meaning.
1. Number theory. This deals with the study of the integers. For instance, Fermat's last theorem is a statement about the lack of solutions to a certain equation. It just says that if n is any integer bigger than 2, it is not possible to find 3 positive integers x, y, and z that make the statement x^n + y^n = z^n come true. It was proven in the mid 90's by Andrew Wiles, who now works at Oxford in a building named after himself. There is a whole BBC documentary on it, and an interview on a YouTube channel called Numberphile with a mathematician named Ken Ribet, who made significant progress on the problem. The proof involves the study of objects called elliptic curves, which can be thought of as a geometric way of visualizing certain equations, sort of like how y=x+1 can be visualized as a line. These equations can then be studied by geometric methods. A whole branch of mathematics, called Algebraic Geometry, studies things like this.
There are basically 2 kinds of number theory: algebraic and analytic. Roughly speaking, algebraic number theory is about generalizing the properties of the integers (looking at other mathematical objects that resemble the integers in certain ways), and analytic number theory is about prime numbers, which are the "building blocks" of integers. There was recent progress on the "twin prime problem": are there an infinite number of pairs of consecutive primes? For example 3 and 5, 11 and 13... Terry Tao mentioned this in an interview on The Colbert Report.
Another question in number theory is called the abc conjecture. A few years ago a Japanese mathematician named Shinichi Mochizuki claimed that he solved it. Unfortunately nobody understands his arguments and in December there will be a conference where he will Skype with some of the world's top mathematicians and try to explain things to them. Some mathematicians think he might be crazy. He refuses to leave his prefecture in Japan (hence the Skyping) and his writing style is eccentric. But this is very much recent stuff! And it looks like he has produced a lot of insight into these general types of problems. There was an article published in Nature about this last month.
2. Representation theory is the study of ways to write a group as a collection of matrices. A group is a collection of objects that satisfy a few axioms which I won't explain further. A matrix is an array of numbers that represents an action on a certain kind of space called a vector space. Such an action is called a linear transformation. Knowing how a group can be represented as a collection of matrices can give more information about that group, and has found applications in chemistry and quantum mechanics!
Number theory and representation theory are actually quite related. Wiles actually proved something called the Taniyama-Shimura conjecture, which is a statement relating elliptic curves to completely different objects called modular forms. A vast generalization is part of the Langlands program, which also generalizes a big part of algebraic number theory called class field theory. It ties much of number theory and representation theory together in very profound ways. It is very exciting because it takes very different parts of mathematics and blends them into each other. At this point it is absolutely impossible to give an ELI5 explanation. Most mathematicians themselves don't know much about it. There is a book called Love and Math, but it is not as accessible as the author would like to believe. The author, Ed Frenkel, also appeared on The Colbert Report.
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"Research is focused on applied mathematics in the broadest sense, with an emphasis on nonlinear systems and solution of problems with industrial relevance. Their fundamental and applied research is relevant to a huge range of real world problems ranging from the dynamics of fish populations in the North Sea to the... |
I often hear that the 'victors write the history books'. How are historians equipped to cut through the supposed propaganda in order to reveal the truth? | This question gets to the heart of current debates across the broader field of History. I caveat that I write this all from my perspective as someone who studies modern political rhetoric, most recently in post-communist Central Europe.
Historians receive all sorts of training about how to address sources, regardless of whether they're supposedly propaganda or not.* Traditional analytical questions often form the base of any historian's initial examination of a document. Who wrote it? When did they write it? Who was their audience?... and similar. These questions are crucial for establishing some basic facts about the document, and also for establishing what you may not know. For example, let's say you see a political poster in the archives but don't know if it was for the 1992 or 1994 election. Your interpretation may well be different depending on that reality, but it also could be relatively similar. In other words, even from the starting point, we run into problems with basic facts about the document.
However, basic facts don't necessarily tell a story. We have to ask questions like "Why did this person write this?" and "What are they not saying, or saying only subtly?" These are difficult questions to answer, even for a well-read historian who knows the subject matter very well to begin with. Finding a purely objective answer is nearly impossible; some historians will argue that it is truly impossible, and that the search for objectivity is worthless.
Others disagree, and say that objectivity can be a relative pursuit; they argue that we can and should accept the answer that is the most accurate compared to all potential answers [1]. This is understandably a matter of great contention.
Ultimately, regardless of your position on objectivity in history, you do need to do some digging, and you'll need your analytical questions to get there.
*In my field of political rhetoric, arguably everything is propaganda. It's almost easier to deal with your question of "truth," because a historian like myself presumes that most sources have some pretty clear agenda. As such, you can't rely on any one source for a baseline narrative, and to draw out any sort of "truth," you need to combine sources, even if you're just caveating and contextualizing the rambling diatribe of a retired politician.
[1] Bevir, Mark. "Objectivity in History." History and Theory 33, no. 3 (1994): 328-44. doi:10.2307/2505477. _URL_0_ | [
"However other critics suggest that this is a \"deliberate attempt to provide alternate readings\" on principle. Teachers' omniscient authority is undermined in sections such as 'Test Your Teacher', which says \"Your teachers will tell you all about the legions and what they wore and how they lived. But they don't ... |
what does the correlation coefficient really mean? | If the correlation coefficient is 1.0, then the two variables move together in lock step. If one variable changes by a given amount, the other variable changes in direct proportion.
If the correlation coefficient is 0.0, then the two variables have nothing to do with each other. If one variable moves, the other does its own thing completely independently.
If the correlation coefficient is 0.6, then about 60% of the change in the dependent variable can be predicted by the first, while 40% of the variation is independent resulting from some other, possibly unknown variable. | [
"A correlation coefficient is a numerical measure of some type of correlation, meaning a statistical relationship between two variables. The variables may be two columns of a given data set of observations, often called a sample, or two components of a multivariate random variable with a known distribution.\n",
"... |
how do we not run out of 'desert'? | Sand blows away exposing more rock. New rock is blasted by more sand at high winds and crumbles it into smaller pieces until they eventually turn into sand. | [
"The term ‘desert’ has been variously applied to areas that lack key services like banks, food access, or even books. The idea of transit deserts was coined by Dr. Junfeng Jiao and Maxwell Dillivan, first appearing in print in 2013. Since that time the concept of transit deserts has been expanded upon and competing... |
why do americans hate paying taxes so much? | Firstly, you mean IRS. Understandable since you aren't American. American culture is deeply rooted on opposition to authority and taxation. One of the principle causes for the American Revolution was taxation. In addition, nobody particularly likes paying taxes, but especially the more conservative and libertarian members of US society disagree on the level of taxation. | [
"\"Why are Americans so willing to pay taxes in order to support a world-girdling national security establishment,\" asked Walt in 2013, \"yet so reluctant to pay taxes to have better schools, health care, roads, bridges, subways, parks, museums, libraries, and all the other trappings of a wealthy and successful so... |
Was life expectancy actually a lot lower pre-1900 even after accounting for the high infant/child mortality rate? | It was, at least for developed countries, lower.
The usual number given for life expectancy is the "life expectancy at birth" (LEB). This is the predicted mean age of death, given the mortality patterns at the time of birth. This can be significantly reduced by infant/child mortality. E.g., if half the population dies before 5 years old, and the other half dies at age 60, the LEB will be between 30 and 35.
It is possible to exclude infant/child mortality. For example, the "life expectancy at 20" (LE20) is the predicted mean age of death for 20 year olds, given the current mortality patterns.
Looking at data for England and Wales:
* _URL_0_
in 1841 the LEB was 42 and the LE20 was 60. This shows the impact of infant/child mortality (and the LE1 of 48, LE5 of 55, and LE10 of 58 give a more fine-grained view). The 2013 LE20 was 82, significantly higher than the 1841 LE20. The greatly reduced impact of infant/child mortality can be seen in the 2013 LEB of 81 (which is higher than even the 1841 LE70).
Basically, not only has modern medicine greatly reduced infant and child mortality, it has also allowed older people to live longer. Diseases such as cancer are much more likely to be successfully treated today, partly due to improved early diagnosis, and partly due to improved treatment. Victims of heart attacks and strokes are less likely to die. Apart from diseases of the very young and the old, those of in-between ages could and did catch infectious diseases, and sometimes die from them (see the differences between the LE20, LE30, LE40, and LE50 in the graph above). These diseases can be more successfully treated today (not always easily, and in the case, e.g., of tuberculosis, but still with much more success than before). Surgery is more likely to be successful, with a much lower chance of infection.
Where there has been a significant chance of death from warfare, LE20 has been lower (in the graph above, the impact of WW2 on life expectancy can be seen; WW1 is also visible, but partly masked by the much greater impact of the Spanish Flu pandemic). Major epidemics/pandemics can reduce life expectancy. These have resulted in decreases in LEB at times in some countries. For example, the AIDS/HIV pandemic had a major impact in some countries (especially in Africa), with reductions in LEB around the turn of the century (with an increase over the last decade or so, due to reduced transmission and improved treatment). | [
"Life expectancy at birth has increased rapidly from the end of World War II, when the average was 54 years for women and 50 for men, as a result of improvements in medicine and nutrition, and the percentage of the population aged 65 years and older has increased steadily from the 1950s. The advancement of life exp... |
How much can you compress water? | The bulk modulus (how much something compresses when it's squished) of water is 2.2 gigapascals, while the ocean depths are about 0.1 gigapascals. That means it compresses by about 5%. | [
"The second section of the paper machine is the press section, which removes much of the remaining water via a system of nips formed by rolls pressing against each other aided by press felts that support the sheet and absorb the pressed water. The paper web consistency leaving the press section can be above 40%.\n"... |
why do you have to pay for .com domain names? where did those websites get them from in the first place? | There is some upkeep required in owning a domain name, so part of the fee goes to support that.
But most importantly, the price needs to be high enough that people can't just buy millions of domain names to sit on them forever and prevent other people from buying them. -- This is a pretty common tactic in business, even for a "low cost" item, you price it higher so that a small amount of people can't use their resources to completely control it just by being first in line.
Think about it this way: You go to the store to get the new hot iPhone. They are free this year. The guy in the front of the line just "buys" all of them. Well, that sucks. So what if we priced it at $200? Well, maybe he buys 2, then the next guy buys 2, and the third buys 1. Having a price on this makes sure that people can't just abuse the system and its a bit more fair. Not completely fair, but far more than free or cheap. | [
"Most .me domain names were purchased as domain hacks in English and, to a lesser extent, Dutch; 71% of names were applied for by applicants in the United States. Because of the possibility of owning pure verb and noun combinations, their prices have stayed high: during the sunrise period, insure.me went for $68,00... |
temperature changing the taste of water | Tasting in general works better when food is hot. This is why most food is eaten hot, and foods that are supposed to be eaten cold can taste weird when warm. (Have you ever eaten warm melted ice cream? It's sickeningly sweet, because when it's cold you don't taste it as much). | [
"This finding ran contrary to much of the learning literature of the time in that the aversion could occur after just a single trial and over a long delay. Garcia proposed that the sweetened water became regarded negatively because of the nausea inducing effects of the radiation, and so began the study of condition... |
What is this animal, and why does it react like it does? | I'm not that kind of biologist, but it looks absolutely fake. | [
"Animal is the fictional wild and frenzied monster who is a drummer of Dr. Teeth and The Electric Mayhem, the fictional band from \"The Muppet Show\". He is one of The Muppets originally created by Michael K. Frith.\n",
"While collecting the animals on their checklist, the crew discovers a small black creature wi... |
How did the distribution of Coast Salish settlements prior to European colonization compare with how modern American/Canadian settlements are distributed? | Great question, and really pertinent too, as lots of scholars focused on Indigenous histories are increasingly looking to geography and, specifically, GIS technology to enhance historical analysis.
From what I've read, yes, generally, prominent Indigenous villages tend to overlap with European settlements, especially in the area of the Salish Sea.
For instance, from Simon Fraser's account of his voyage down the river that now bears his name, we know that he and his men stopped in a number of Coast Salish villages after leaving Nlaka'pamux territory. Comparing this data with subsequent reserve creation, and then correlating it again with reference to contemporary urban centers, we can see that Ts'elxwéyeqw lands became a series of small reserves, around which the city of Chilliwack and town of Sardis have subsequently been built. The same is true for Katzie villages in the area of New Westminster, and of course Musqueam centers in what is now Vancouver. Or, take the town of Mission, also on the Fraser River, which was established by Catholic missionaries because many Coast Salish people lived, met, or traded in that area.
On the other hand, of course not all significant village sites have become contemporary cities; for instance, a former rock wall fortress surrounded by house pits called Xelhalh, which was clearly a prominent Stó:lō site has, as Wenona Victor explains, "somehow escaped White settlement and encroachment." Victor goes on to describe walking through the archaeological remains at the site as "very much like walking through a ghost town." See Victor, "XeXa:ls and the Power of Transformation," (PhD dissertation, Simon Fraser University, 2012) 165-166. [Link to PDF here.](_URL_0_)
Lots of historians have done great work on this topic. I urge you to check out these titles for more specific information:
Carlson, Keith Thor, ed. *A Stó:lō-Coast Salish Historical Atlas*. Vancouver: Douglas & McIntyre, 2001.
Harris, Cole. *Making Native Space: Colonialism, Resistance, and Reserves in British Columbia*. Vancouver: UBC Press, 2002.
Thrush, Coll. *Native Seattle: Stories from the Crossing-Over Place*. Seattle: University of Washington Press, 2007. | [
"The southern and east coasts were, of course, the areas settled first and in greatest numbers by the settlers and so presumably were the earliest to pass from Romano-British to Anglo-Saxon control. Once established they had the advantage of easy communication with continental territories in Europe via the North Se... |
president obama's plan to allow workers who make less than ~$50k/year on salary to qualify for overtime. | Most Americans who are employed by a company are paid in one of two ways. Either you are paid a set rate for each power of work or you are paid a salary per year.
If you are paid by the hour, then working more hours will earn you more money. There is also a rule that if you work "overtime" – more than "full time", which is forty hours in a given week – then hours above forty are paid at a higher rate.
If you are salaried, working more or fewer hours will not change your pay. However, there is still a rule that you have to be paid more for working "overtime". But there is an exception. If your salary is more than a certain amount, and a few other conditions are satisfied, you may be "exempt" from earning overtime pay. This exemption is meant for upper-middle-earning managers and professionals. However, the threshold for exemption did not rise over time with inflation, so that many lower-earning Americans worked overtime and were not paid for it. Now, the threshold is higher, more like what it used to be (adjusted for inflation), so it once again applies to people who earn higher salaries. | [
"Obama also issued several executive orders and his administration issued regulatory rulings designed to help workers. One included raising the salary threshold above which employers do not have to pay overtime, from $455 to $913 per week. This would have increased the earnings of as many as 4.2 million workers beg... |
How much of an effect do the Sun and the Moon have on the Earth's axial precession, if any? | The gravitational force of the sun and the moon on earth's equatorial bulges is the reason why the earth's rotational axis precesses in the first place.
The period of the precession is ~26.000 years, the nutational period is ~18.6 years. The sun contributes about 1/3 and the moon 2/3 of the force. Without the two bodies, earth's axis would not precess. [Here you can read a detailed overview](_URL_0_). | [
"The solar equation is a good representation of precession due the Sun because Earth's orbit is close to an ellipse, being only slightly perturbed by the other planets. The lunar equation is not as good a representation of precession due to the Moon because the Moon's orbit is greatly distorted by the Sun and neith... |
how does nano technology work and can we get objects, such as tiny cameras, into little creations that can fly? | Asking that is like asking “how does normal sized tech work”. Nano is just a prefix used here to describe the general size of an object.
The reason it’s considered special “nanotechnology” is that it’s hard to create these objects and it’s hard to come up with new ways of cutting corners to bring down total size. | [
"Many researchers are looking into creating nano-scale robots (“nanobots”), for the purpose of undertaking tasks where only robots on the nano scale can be used, such as inside the human body. These robots would have the ability to construct other nanostructures or perform medical procedures, and will be introduced... |
how does a thumbprint sensor on a mobile device work, and why does it have to be recalibrated every once in a while? | Most fingerprint scanner are made of capacitive touch sensors, just like the ones on most touch screens. The simple explanation is that it's a bunch of capacitors, which are devices that can store small amounts of electrical charge. The capacitors are tiny, smaller than the ridge of a fingerprint. When you touch a capacitor, at least one this small, it changes how well the capacitor can hold a charge. Since a ridge on your finger makes direct contact it changes how much charge the capacitor can hold more than a valley on your fingerprint, which has a layer of air between it and your skin. The sensor then basically measures the difference in voltages across all of the sensors, and can tell which capacitors are in contact with your skin (ridges) and which have the layer of air between them (the valleys). It can use this to then construct a kind of image of what your fingerprint looks like.
What it does with that image probably depends on the phone. Usually they look for significant features like where ridges and valleys intersect and tries to find matches for those, as opposed to making sure every ridge and every valley lines up with what it has stored since that would be computationally more work and also more prone to problems.
Why do you have to recalibrate it? Well that depends on a lot of things. I've never had to recalibrate mine, but it could just be the equipment stops working properly, maybe the sensor is dirty, but you shouldn't have to redo it normally if everything works as intended. | [
"Other features include an earpiece with built-in notification LED, a fingerprint sensor on the phone's back side, an infrared port allowing the phone to act as a universal remote, dual SIM-card support in select versions, a USB 2.0 with Type-C interface connector, and QuickCharge support. In addition to scanning f... |
What is the function of having 2 bones in our lower arm, radius and ulna, instead of one like the humerus? Same with the legs. | The two bones in the forearm is for more movement. If you hold out your arm with the palm up, the two bones are parallel. Now if you turn your palm to face down, the thumb side bone, radius, is now crossed over the ulna. The two bones add much more movement than one bone. There are two bones in the lower leg, but that has more to do with stabilization for walking. | [
"The humerus is one of the three long bones of the arm. It joins with the scapula at the shoulder joint and with the other long bones of the arm, the ulna and radius at the elbow joint. The elbow is the hinge joint between the end of the humerus and the ends of the radius and ulna. The humerus cannot be broken easi... |
How do communities on deep ocean vents populate new vents as theirs dies away? | I just asked my friend who recently finished her Ph.D in deep sea hydrothermal vents this question, here is her reply:
well no one really knows. all vent animals have highly dispersible embryos and they travel in the water column till they find a vent
but we dont really know much. some travel with vent plumes, others take advantage of bottom ocean currents
based on the species they have different lenghts of survivial in the water column,
some of them are non feeding and have big yolk preserves to go far,
others are feeding and rise somewhat in the water column and then who knows how and when they sink to find a vent.
Edit:
I'm actually gonna be hanging out with her tonight and I'll have my phone on me to see replies to this comment if anyone wants to do an AMA with a deep sea hydrothermal vent PH.D | [
"Hydrothermal vents were first discovered in the ocean depths in 1977. They result from seawater becoming heated after seeping through cracks to places where hot magma is close to the seabed. The under-water hot springs may gush forth at temperatures of over and support unique communities of organisms in their imme... |
The US declared independence in 1776. The Holy Roman Empire was around until 1806. Do we know of any diplomatic contact between these two nations? | Vienna sent a trade delegate to the US directly after the signing the Treaty of Paris at 1793. Albeit no arrangements were made amongst Empire and US since Emperor Joseph II did not recognize the US. In this manner there was no formal connection amongst the Empire and US until 1802, when Emperor Franz II endorsed a US consulate in Trieste. This implies that at least Franz II, as the HRE emperor at that time, recognizes the US.
So suppose HRE, as a diplomatic entity, finished in 1804 when Franz II changed his title from HRE emperor to the emperor of his recently established Austrian Empire. In fact there should in any case be a multi year time span somewhere in the range of 1802 and 1804 when US and HRE formally recognize each other. Edit : fixed typo | [
"Before and during the American Revolutionary War, the Catholics in Great Britain's thirteen colonies in America (and also its colonies in Canada) were under the ecclesiastical jurisdiction of the bishop of the Apostolic Vicariate of the London District, in England. After the Treaty of Paris, signed September 3, 17... |
why do people stick a 'sold' sticker on a previously 'for sale' house's billboard? | Because it's still an advertisement for the real estate agency, and it shows results. You see a "sold" sign and people can see that the agency is doing its job. | [
"Press reports and police warnings suggest that the stickers used are intended to look innocuous, so that even if the property's owner or tenant spots the sticker, they may leave it in place. The stickers typically advertise the services of a locksmith.\n",
"Stickers can come in many different shapes and sizes an... |
Why do so many very different species all have red blood? how far back in our evolutionary timeline can we be sure that things had red blood? | The colour red is mostly due to the heme prosthetic group (forming haemoglobin, a globular protein) which carries a ferrous ion (Fe^2+) in its center, which will take the oxygen molecule (or CO2, CO, HCN, etc.), converting into the ferric ion (Fe^3+) until it releases it somewhere else. That's why we need to consume iron.
Certain animals, such as crustaceans and cephalopods (octopi, cuttlefish, etc.), instead of having the hemo prosthetic group, they have the cyano prosthetic group, which carries a copper atom instead of an iron atom, and that gives their blood a blue colour. Functions the same by being in a cupric ion state (Cu^2+), just that the atom is different, and therefore so is the colour. | [
"Vertebrate blood is bright red when its hemoglobin is oxygenated and dark red when it is deoxygenated. Some animals, such as crustaceans and mollusks, use hemocyanin to carry oxygen, instead of hemoglobin. Insects and some mollusks use a fluid called hemolymph instead of blood, the difference being that hemolymph ... |
Didn't eating red meat used to cause cancer? What happened to that? | I've mentioned it before, but I would be very skeptical about links between specific types of food in the diet and cancer. For some things, people aren't able to acurately quantify how much they eat. People know that they smoke a pack a day or have a six pack each night, but self-reporting of diet over things like vegetables, red meat, etc are less reliable. I know there's no way that I could tell you how many ounces of red meat I ate over the past week. I can't even remember half my meals.
Next, studies that survey just link two things. They might establish correlation, but not causation. To progress from correlation to causation, you would like to have some additional parts to your theory. One is a reasonable mechanism where it sounds like A can cause B. The second is that you would like event A to coincide with B. However, this is complicated because people eat for 60 years, then develop cancer. It's not as if one day they develop cancer from the steak they had the night before. You can have false correlations without causation from things like, environmental factors associated with self-reporting of food intake. For example, people who drink red wine tend to live a healthier lifestyle than people who drink beer and they do better health-wise. But it's their lifestyle, associated with socioeconomic status, that gives them better health, not the wine.
Now I think diet may contribute, but I don't think it has much effect as long as you're not overweight and you take in a sufficient amount of vital nutrients. To recap, take these studies with a grain of salt because self-reporting diet is often not accurate, I am not convinced by the models presented to link food to cancer, the exposure is chronic with a large temporal association between exposure and supposed consequence, and there are a lot of possibilities for confounding variables.
| [
"On October 26, 2015, the International Agency for Research on Cancer of the World Health Organization reported that eating processed meat (e.g., bacon, ham, hot dogs, sausages) or red meat was linked to some cancers.\n",
"BULLET::::- The International Agency for Research on Cancer of the World Health Organizatio... |
why does it take longer for an iphone to charge from a dead state to a percentage to turn back on than the same percentage charge takes when the phone is not dead? | The percentage is a little bit arbitrary. The percentage is determined from the voltage, which is not linearly related. So someone had to actually decide how it would relate. Surely they did a lot of work to ensure that it's close but it's but going to be perfect.
Then on top of that, that voltage is not linearly related to the charge of the battery. So there's more separation between the number and the actual charge of the phone.
Finally, the percentage is actually purposely fudged, to hide the fact that when left plugged in, it bounces around 95-100%. And constantly recalculated to try to be more accurate.
So basically, the number it gives you is not actually a super accurate representation of what's going on. *Especially* if you are at the extreme of an almost drained battery.
| [
"\"The Next Web\"s Juan Buis wrote in late November 2016 that \"complaints are shared [on Apple's support forums] about various iPhone models turning off when the battery falls below a certain percentage\", and blames the iOS 10.1.1 update. He further wrote that \"the original post [on support forums] explains that... |
Since pink isn't on the color spectrum, does it actually exist? | The color pink exists. "Pink" photons, do not exist. The color spectrum describes the wavelength of photons (Green is ~532 nm, Red ~700 nm, Blue ~460). There is no wavelength that corresponds to pink. Instead, what you see as pink is a combination of wavelengths that you interpret as pink. See [this](_URL_0_) chart. The outer curve shows the visible spectrum, the inner sections shows combinations that we interpret as different colors. Notice that white is in the center as it is a combination of the entire visible spectrum. | [
"Purple, unlike violet, is not one of the colors of the visible spectrum. It was not one of the colors of the rainbow identified by Isaac Newton, and it does not have its own wavelength of light. For this reason, it is called a \"non-spectral color\". It exists in culture and art, but not, in the same way that viol... |
how does the sky appear red in australia right now? | Thick smoke lit from below by massive fires, and filtering the sunlight in the same way lots of atmosphere does (which is why sunsets are red). | [
"Approximately true-colour \"in situ\" images from the Mars Pathfinder and Mars Exploration Rover missions indicate that the Martian sky may also appear reddish to humans. Absorption of sunlight in the 0.4-0.6 µm range by dust particles may be the primary reason for the redness of the sky. An additional contributio... |
There's a TIL on the frontpage that voter fraud likely got Kennedy elected over Nixon. Is there any reputable evidence for this? | Please note that, in AskHistorians, the onus is on *you* to provide appropriate evidence for the historical claims you make. Stating that it can be found on Google is not helpful. Mentioning something you may have heard once is not helpful. Guessing based on what you remember from X number of years after the event is not helpful.
Proper comments for this subreddit should be in-depth, comprehensive, and informative while properly situating the answer in its historical context. It should also be backed by appropriate primary and secondary sources, whether or not explicitly mentioned in the comment (i.e. you should always be ready to provide sources *if asked*). In other words, answers here should be such as an historian of the subject would give.
Thank you. | [
"Some, including Republican legislators and journalists, believed that Kennedy benefited from vote fraud from Mayor Richard Daley's powerful Chicago political machine. Republicans tried and failed to overturn the results at the time—as well as in ten other states. Some journalists also later claimed that mobster Sa... |
How are polarized lenses made? | Imagine taking a screen from a window, and stretching it diagonally. The holes in the screen stretch one way and shrink the other. We can imagine what might happen if we had a long, thin knife: we could slide it through very easily if we aligned it with the stretched holes, but in any other orientation, it doesn't go through the screen.
Polarizers are made the same way. A resin or plastic film is heated and stretched, and the intermolecular spacing takes on the same characteristics as our stretched screen. Thus, the wave of the photon (the electric field vector, actually) passes through unhindered when it's aligned with the polarizer, and is absorbed by the resin in any other orientation. | [
"Circular polarizers can also be used to selectively absorb or pass right-handed or left-handed circularly polarized light. It is this feature which is utilized by the 3D glasses in stereoscopic cinemas such as RealD Cinema. A given polarizer which creates one of the two polarizations of light will pass that same p... |
Are spiral galaxies accretion discs for supermassive black holes? | No. The supermassive black hole at the center of a galaxy has virtually no interaction with the rest of the galaxy not near the centre. | [
"The most spectacular accretion disks found in nature are those of active galactic nuclei and of quasars, which are thought to be massive black holes at the center of galaxies. As matter enters the accretion disc, it follows a trajectory called a tendex line, which describes an inward spiral. This is because partic... |
What was the significance of Charlemagne's coronation in 800? | This is a great question, one clarifying question though. Do you mean its significance to contemporaries of the time, or people later on? | [
"Charlemagne was crowned by Pope Leo III in Old St. Peter's Basilica on Christmas Day of 800, with an aim to re-establishing the old Roman Empire. Charlemagne's political successors continued to rule much of Europe, with a gradual emergence of the separate political states that were eventually to become welded into... |
what are banned books and why are we celebrating them? | No, many of them *are literally banned* in certain parts of the world. We celebrate them because people have a right to know and there are many institutions and governments in the world that try and suppress forms of thinking or don't want their people to know certain things.
Harry Potter is banned in some counties because people think it encourages witchcraft and sorcery. The Anarchist Cookbook details how to make explosives from commonly obtainable chemicals and household items. Lady Chatterley's Lover was banned in the United Sates and a few other countries for violating obscenity laws.
Its a way of celebrating freedom of expression and information with a bit of civil disobedience thrown in.
Here's a list of books banned by country [for your reading](_URL_0_) | [
"Banned Books Week is an annual awareness campaign promoted by the American Library Association and Amnesty International, that celebrates the freedom to read, draws attention to banned and challenged books, and highlights persecuted individuals. Held during the last week of September since 1982, the United States ... |
Modern speakers of Sumerian? | Hello!
If I could plug my own, have a look at this recent post discussing what [contemporary scribes knew about Sumerian and how much is known by modern Assyriologists.](_URL_0_)
| [
"Sumerian ( \"native tongue\") is the language of ancient Sumer and a language isolate that was spoken in Mesopotamia (modern-day Iraq). During the 3rd millennium BC, an intimate cultural symbiosis developed between the Sumerians and the Semitic-speaking Akkadians, which included widespread bilingualism. The influe... |
Did Helot slaves ever gain independence after the end of Spartan Dominance? | Yes. In 371 BCE, the Thebans under their general Epamonidas defeated the Spartans at Leuktra, in Boeotia. It was Sparta's biggest defeat in centuries, and the next year (in 370 BCE) the Thebans invaded the Peloponnese and liberated a portion of the helots. Sparta had several different populations of helots, including "local" Lakonian persons and also a large number of "foreign" groups which had long been dominated by Sparta. In 370, the Thebans liberated the helots of Messenia, after which they founded a new city Messene on Mount Ithome, in their ancestral homeland. The helots in the Spartan homeland, however, remained in slavery. They would slowly, over the centuries, gain various aspects of independence under varous reformist rulers. | [
"Some texts mention both slaves and helots, which seems to indicate that they were not the same thing. Plato in \"Alcibiades I\" cites \"the ownership of slaves, and notably helots\" among the Spartan riches, and Plutarch writes about \"slaves and helots\". Finally, according to Thucydides, the agreement that ended... |
Could r/askhistorians advise me on possible titles to add to to my reading list/collection on various topics? | Take a look at the side bar. Down near the bottom is a book list complied by Tiako which is chock full of good titles in the areas you want to learn more about. | [
"Additionally, \"Booklist\" selects Editors’ Choice lists for adult books, young adult books, books for youth, adult audiobooks, and audiobooks for youth. The best title in each category is selected to a list known as Top of The List. Editors' Choice and Top of the List titles are announced in December and printed ... |
how can cable send hundreds of hd channels at the same time but my internet is slow? | It's the difference between using a megaphone to talk to 100 people, and using 100 telephones to talk to 100 people. There is no two-way communication with cable (TV at least), and you are only handling 1 signal instead of a separate signal for each person. | [
"Downstream, the direction toward the user, bit rates can be as much as 400 Mbit/s for business connections, and 320 Mbit/s for residential service in some countries. Upstream traffic, originating at the user, ranges from 384 kbit/s to more than 20 Mbit/s. Broadband cable access tends to service fewer business cust... |
comcast. | In most cases it's because Comcast has exclusive agreements with local governments, so the choices come down to them or nobody for many people, or at best them or slow DSL for Internet. | [
"The Comcast Corporation is the largest mass media and communications company in the world by revenue. It is the largest cable company and home Internet service provider in the United States, and the nation's third largest home telephone service provider. Comcast has a monopoly in Boston, Philadelphia, and many oth... |
when you work out/do cardio do you burn the same amount of calories when you first start off compared to when you are conditioned if you do the same workout? | Yes, as you get more in shape, your body becomes more efficient at exercise, and you burn less calories. This effect is mediated by the fact that more in shape people can exercise at a higher intesity rate, usually more than enough to compensate for the increase in effiency.
For example, if you start running 5k every day. After a few weeks, you will be burning less calories than when you started, but you should be able to run those 5 kilometers either much quicker or with much less effort than when you started. Suppose instead, you decide to simply run 30min at medium intensity. After a few weeks you will be burning more calories because the increase in speed will mean that you can cover more distance in the same amount of time.
Furthermore, people often find it easier to lose weight when they are very overweight to start with. Partially this is because it takes more work to move a heavy body than a light one. If you lose a lot of weight, the same exercise may not burn as much calories as before because you don't have as much weight to move around. This is when you need to start adding weight to keep the difficulty of the exercise the same. | [
"Some theorists believe the metabolic window begins to close within minutes of the end of a workout. They claim the same nutrients taken two hours later result in significantly reduced protein synthesis and muscle glycogen storage. Further research is needed into the effects of food and exercise timing, but methodo... |
How was the king in England elected in the Middle Ages? | I think it would probably be easier if you narrowed down this topic a bit in terms of chronological scope. You could compare English/German kings in the Early Middle Ages, High Middle Ages, or Late Middle Ages, but I think trying to cover the differences/similarities throughout the entirety of the medieval period might be difficult (because things can change CONSIDERABLY).
That said, I am most familiar with French high medieval history, so I don't have a whole lot to recommend in terms of reading, and certainly not in German. I would say that there might be some useful information for the English side in Robert Bartlett's *England Under the Norman and Angevin Kings, 1075-1225*. I would imagine, at the very least, you might find some even more useful resources in his bibliography directly relating to kingship in England. | [
"In the Medieval period, government in England was very much centred on the King. He ruled personally, usually assisted by his Council, the Curia Regis. The council members were chosen by the King, and its membership varied greatly, but members often included powerful nobility and churchmen, senior civil servants, ... |
the "iron peak" in nuclear reactions | The force holding protons and neutrons together in atomic nuclei is called the [nuclear force](_URL_0_), and is a a part of the strong force, but has a very limited range, so for large nuclei begins to weaken. On the other hand, you have the electrostatic forces trying to push the protons apart, since they all have a positive charge. This does depend on distance too, but not as strongly as the nuclear force.
When a nucleus gets large, the nuclear forces get weaker in general, whereas the electrostatic forces get larger due to the increased numbers of protons. | [
"The alpha process, also known as the alpha ladder, is one of two classes of nuclear fusion reactions by which stars convert helium into heavier elements, the other being the triple-alpha process. The triple-alpha process consumes only helium, and produces carbon. After enough carbon has accumulated, the reactions ... |
Do 3D glasses need to be tinted? Or is there a way to polarize a lens so that it does not have the tint? | If you could view the waves in a lightbeam coming towards, you would see the waves oscillating in all directions- up & down, left & right, and all angles in between. The 3D glasses you are referring to have polarizing film in them that allow only light waves with a certain orientation to pass through, let's say up & down. As a result, the left & right waves are completely blocked. Waves that are slightly off the up & down axis will mostly pass through, while those that are slightly off the left & right axis will barely pass through.
The end result is that a polarizing film will reduce the intensity of non-polarized light by 50% - hence the sunglass effect. | [
"Anaglyph 3D glasses have a different colored filter for each eye, typically red and blue or red and green. A polarized 3D system on the other hand uses polarized filters. Polarized 3D glasses allow for color 3D, while the red-blue lenses produce an image with distorted coloration. An active shutter 3D system uses ... |
why do people get sore throat when they keep eating chocolate? | The sugar in chocolate candy dehydrates you, and that makes your throat burn. Oddly enough, hard candies made with pectin and sugar will coat the throat, and can soothe sore throats. | [
"Chocolate may be a factor for heartburn in some people because one of its constituents, theobromine, may affect the esophageal sphincter muscle in a way that permits stomach acids to enter the esophagus. Theobromine poisoning is an overdosage reaction to the bitter alkaloid, which happens more frequently in domest... |
How long did it take for knowledge of European contact with the Americas to spread across Europe, Africa, and Asia? What did normal people think about it? | As a follow-up (and let me know if this should be a separate post), did Europeans, both wealthy and common folk, initially view Native American peoples as culturally inferior and, if not, how long did it take for that perception to become widespread? | [
"After 1492, European exploration and colonization of the Americas revolutionized how the Old and New Worlds perceived themselves. Many of the first major contacts were in Florida and the Gulf coast by Spanish explorers.\n",
"Other Explorers such as the Spanish sponsored Italian Christopher Columbus intended to e... |
please explain to me preference utilitarianism as a belief system/religion? | Utilitarianism is a system of belief based on making and doing things that have use. Utilitarianistic design has less flair and more practicality.
By extension, Preference Utilitarianism is a system where morals are defined based on how things make people feel.
If I kill you because youre a murderer, morally I'd be fufilling the preference utilitarianist system if that makes people happy.
If I kill you because you design cheap houses that are affordable, a preference utilitarianist society would be unhappy and as such, by the system, Id be in the moral wrong | [
"Utilitarianism (from the Latin utilis, useful) is a theory of ethics that prescribes the quantitative maximization of good consequences for a population. It is a form of consequentialism. This good to be maximized is usually happiness, pleasure, or preference satisfaction. Though some utilitarian theories might se... |
how does a phone vibrate? | An unbalanced weight, called a counterweight is mounted on the end of the shaft of a small high speed electric motor inside the phone.
When the motor spins the counterweight causes the phone to vibrate.
Here's a decent explanation with some visuals...
_URL_0_
| [
"When smartphones and pagers vibrate, the vibrating alert is produced by a small component that is built into the phone or pager. Many older, non-electronic buzzers and doorbells contain a component that vibrates for the purpose of producing a sound. Tattoo machines and some types of electric engraving tools contai... |
Are there any lifeforms that don't rely on sunlight (even indirectly)? | The chemoautotrophic bactieria you mention "use sulfur compounds, particularly hydrogen sulfide, a chemical highly toxic to most known organisms, to produce organic material through the process of chemosynthesis." [_URL_0_](_URL_1_) | [
"The sun is the primary source of energy for living organisms. Some living organisms like plants need sunlight directly while other organisms like humans can acquire energy from the sun indirectly. There is however evidence that some bacteria can thrive in harsh environments like Antarctica as evidence by the blue-... |
since light is flying about in all directions from all surfaces, how come don't just see a blurred mix of all the light entering our eyes? | This is what the lens of our eyes does. It focuses light from one direction into our eyes, and doesn't allow light from other directions to enter. | [
"As objects radiate light in straight lines in all directions, the eye must also be hit with this light over its outer surface. This idea presented a problem for al-Haytham and his predecessors, as if this was the case, the rays received by the eye from every point on the object would cause a blurred image. Al-Hayt... |
If prokryotes don't have any cloroplasts how do they, and other bacteria, obtain energy and where in the cell? | First clue is that mitochondria are very similar to bacteria and are thought to have originated from bacteria. Bacteria without chloroplasts obtain energy (that is, produce ATP molecules) a similar way mitochondria do, they use the oxidation biochemical reactions that are found in their plasma membrane (analogous to the mitochondrial membrane). | [
"Protoplast, from ancient Greek (\"prōtóplastos\", \"first-formed\"), is a biological term coined by Hanstein in 1880 to refer to the entire cell, excluding the cell wall. Protoplasts can be generated by stripping the cell wall from plant, bacterial, or fungal cells by mechanical, chemical or enzymatic means. \n",
... |
Is there an animal that loses the ability to fly? | In the case of insects one thing is very important here: flying insects only have wings when they are in the adult stage. So there are no larvae/nymphs that have wings and then after metamorphosis lose them. However, there are insects that have wings and lose them! A perfect example are ants; ant queens have wings but after mating during their [nuptial flight](_URL_0_), the wings fall off and the ant queen moves underground. This is similar for termite queens and kings. The wings have a dispersal function and when dispersal is no longer needed (since a colony will be started) the wings are lost (having wings impedes locomotion underground). | [
"Blood loss is a common problem in some animals when large flies are abundant. Some animals have been known to lose up to of blood in a single day to tabanid flies, a loss which can weaken or even kill them. Anecdotal reports of horse-fly bites leading to fatal anaphylaxis in humans have been made, an extremely rar... |
how do we know how fast the sea level rose 2000 years ago? | Here is the blog of one of the scientists in the study. _URL_0_
On the second page, you'll see they talk about drill cores of coastal sediments, and here is an article talking about how that is done: _URL_1_
The new paper uses statistical modelling techniques to use a wide variety of data points from those drill cores from around the world to produce the sea level rise (independent of factors like land uplift, etc., etc.). | [
"BULLET::::- 8,200–7,600 years ago (6200–5600 BC): sudden rise in sea level (Meltwater pulse 1C) by 6.5 m in less than 140 year; this concludes the early Holocene sea level rise and sea level remains largely stable throughout the Neolithic.\n",
"The sea level has risen more than since the [[Last Glacial Maximum]]... |
why does fog in a forest look brighter than the actual forest itself even though there is no light source anywhere near it? | The fog is white, while the forest is colored. Anything white on a colored background looks brighter than the background, because white reflects more light than any other color. | [
"Fog shadows may look odd to viewers who are not used to seeing shadows in three dimensions. A thin fog is just dense enough to be illuminated by the light that passes through the gaps in a structure or in a tree. As a result, the path of an object's shadow through the fog becomes visible as a darkened volume. In a... |
how does marijuana/other drugs give you a uppy feeling and or make you see things? | All drugs function by binding to other molecules or cellular structures. The ones that produce mind-altering effects are binding to molecules and cellular structures in the brain that regulate our emotions and perceptions. This changes how active or effective those molecules or cells are, which changes how we feel or interpret the sensory data we receive. | [
"Cannabis, psychedelics, dissociatives, antidepressants, caffeine, nitrous oxide, albuterol, and nicotine can all produce feelings resembling derealization, particularly when taken in excess. It can result from alcohol withdrawal or benzodiazepine withdrawal. Opiate withdrawal can also cause feelings of derealizati... |
is it safe for people to live in places like hiroshima and chernobyl now? | [Hiroshima](_URL_0_) is safe, there's over a million people living there now.
The other reactors of Chernobyl continued to operate, they only started decommissioning them in 2015.
They evacuated the area and limit how long people can stay near the power plant, but they still allow it.
The reason Hiroshima quickly recovered is that there was only as much nuclear material as could fit in one bomb, Chernobyl had a lot more stuff on hand and a lot more stuff got out. | [
"In a 2017 risk analysis, relying on the metric of potential months of life lost, it determined that unlike Chernobyl, \"relocation was unjustified for the 160,000 people relocated after Fukushima\", when the potential future deaths from exposure to radiation around Fukushima, would have been much less, if the alte... |
Is 'Rise and Fall of the Third Reich' discredited? | Here are a few previous answers talking about Shirer, his work (at least this book), and it's place as primary source.
1. /u/Kochevnik81 lil bit [here](_URL_4_)
2. /u/kieslowskifan lil bit [here](_URL_3_)
2a. /u/Georgy_K_Zhukov put down an alternative work by Richard J. Evans found in the booklist [here](_URL_2_)
3. a bit of a thread can be found [here](_URL_0_) by [deleted] heh, and maybe some other discussions there as well.
4. /u/naturalog lil bit [here](_URL_1_)
might find more searching under the book title but these are good starts. | [
"In 2004 the historian Richard J. Evans, author of \"The Third Reich Trilogy\" (2003–2008), conceded that \"Rise and Fall\" is a \"readable general history of Nazi Germany\" and that \"there are good reasons for [its] success.\" Evans contended that Shirer worked outside of the academic mainstream and that Shirer's... |
How were the subduction zones discovered and observed? | Ooooh. Very short version. During ww2, destroyers crossing the Atlantic ran their sonar full time looking for submarines, and kept a paper record. After the war, a guy examined all that data and discovered the mid Atlantic ridge. He looked at the coastline and the ridge and hypothesized plate tectonics. Since the mid Atlantic ridge is creating new crust, it must be going somewhere... the subduction zones were found shortly after.
Remember kids, before this, geology, which is a very old science had little notion of such a thing (yes, it was proposed before, but with little evidence). Geologists had theories about why the world looked the way it did, and they were wrong. The point is, a huge scientific discovery, with giant repercussions was only recently discovered. There is still lots to be figured out in this world. | [
"Subduction zones are areas where one lithospheric plate slides beneath another at a convergent boundary due to lithospheric density differences. These plates dip at an average of 45° but can vary. Subduction zones are often marked by an abundance of earthquakes, the result of internal deformation of the plate, con... |
Crew size of ancient and medieval sailing ships? | Since medieval culture was very diverse, so were shipbuilding styles.
Viking style:
The [wiki article](_URL_1_) is pretty good and has an excellent list of external links for the layman. You can usually estimate their crew size easily by counting the number of oar holes: Warships tend to have more (one paddle per soldier) than tradeships - 30 - 40 oars, plus some more space for additional soldiers, supplies, even horses could be part of the load. The tradeships had no oar holes midship, and also were built more rotund, strengthened in the midship, where the cargo was. Their crew could be as low as 10 people. Baltic sea ships tended to be on the smaller side, and North sea trade ships could have up to about 20 crew. Typical tonnage was about 8 - 30 tons, with single ships of up to 150 tons excavated. They also tended to be very much more plain than warships or the ships that were used to [bury important people in](_URL_5_).
Then there's the [cog](_URL_2_), known in many incarnations, from a small fishing boat during the Early Middle Ages up to a sizeable trade ship and the main workhorse of the [Hanse](_URL_3_) during the High Middle Ages. They were typically bigger, starting at about 25 tons, typically having between 100 and 140 tons, and reaching up to 200 - 380 tons for long distance trade ships (e.g. the trip to Flanders). Modern replicas of the medium sized ships need about 10 people for safe handling, in times of war (yes, they were adapted if need be - there wasn't much of a specialization regarding warships back then) they could have several hundred people aboard.
Thirdly, the [Hulk or Holk](_URL_4_), a predecessor of the [Caravell](_URL_0_) (the type of Ship Columbus used), that more or less fused with or displaced the Cog in the Late Middle Ages, even in the Hanse (that was breaking up by then, anyway). They were typically bigger (smaller side: 180 tons, typically 300 tons, up to 700(!) tons), more robust, easier to steer (better construction in terms of a rounder steven and more defined keel), but, since crew lists of this time (early 16th cenctury) typically contain a good part of soldiers for protections against pirates, crew sizes are hard to estimate.
I hope that's a nice enough overview/Starting point. Sorry, but my sources are all German, but if someone's interested, I'll post 'em. | [
"Mycenaean ships were shallow-draught vessels and could be beached on sandy bays. There were vessels of various sizes containing different numbers of oarsmen. The largest ship probably had a crew of 42–46 oarsmen, with one steering oar, a captain, two attendants and a complement of warriors.\n",
"The most common ... |
Is it possible to simulate pressure equivalent to the level where anglerfish reside underwater, but in aquariums? | in principle -though many deep fish can live at surface pressures if brought up very slowly and carefully (it is often the abrupt change that kills them). see _URL_1_
The Shedd aquarium in Chicago has experimented with pressure tanks for jellyfish and sea horses see _URL_0_ | [
"Visitors can take part in an animal encounter. It is possible to snorkel in the lagoon with approximately 1500 fish. Underwater adventures including shark cage diving and walking on the floor of the aquarium with an ocean diver are also available.\n",
"The fish has a pair of primitive lungs instead of a swim bla... |
would a baby look different if the parents were young when it was conceived, rather than old? | This is the idea of [Lamarckism](_URL_0_), which was a popular theory for evolution prior to and contemporary with Darwinism. Larmckism basically says that characteristics aquired by parents in their lives would get passed on to their offspring... sort of. For example, say an organism lost its right forelimb and then later became a parent. Lamarckism would expect to see the offspring have a slightly shorter right forelimb.
Your question is the same idea: would aging affect the child? This is not the case because our DNA doesn't really change throughout our lives. The DNA you get when you are born is the same as when you die. And it is the mixing of the parents' DNA that determines the look of the baby/child. | [
"Two baby boys, born more or less at the same time, were switched soon after they had been born. When their families accidentally discover it eighteen months later, they start having troubles to decide who their real children are – the one they have been raising or the one they gave birth to.\n",
"In specified ca... |
Would a sandwich that was in space and re-entered Earth's atmosphere be edible? | If it wasn't incinerated on reentry into the atmosphere, yes. | [
"Bauman and his team were instrumental in creating the first solid food consumed by a NASA astronaut: small food cubes eaten by Scott Carpenter on board \"Aurora 7\" in 1962. (John Glenn had consumed the fruit-flavored drink Tang in space three months earlier aboard the \"Friendship 7\".) Space food cubes were foll... |
will a more obese person burn more calories with the same daily activity as a thinner person strictly because of the amount of effort necessary to keep up? | Yes, absolutely. Hauling a 300 pound body up a flight of stairs takes around twice as much work (and calories) as a 150 pound body. | [
"BULLET::::- There is no evidence that obesity is related to slower resting metabolism. Resting metabolic rate does not vary much between people. Weight gain and loss are directly attributable to diet and activity. Overweight people tend to underestimate the amount of food they eat, and underweight people tend to o... |
if light is mass-less, what is keeping it from having an infinite velocity? | This is *exactly* the line of thinking which started Einstein on the path to relativity. His solution was to posit that the speed of light *is* infinite from the standpoint of the universe. This is why it is never possible to exceed, or even reach, the speed of light in a vacuum. So it’s less that the speed of light is a cosmic speed limit that nothing can ever surpass, and more that it’s a cosmic horizon that nothing can ever catch up to.
The triumph of relativity is in explaining why it is that light doesn’t instantaneously propagate between two points in space. How it does this gets quite complicated, but one way to think about it is that the time it takes light to move from one point to another is actually the time it takes for space time itself to change to accommodate a changed state in some other location. The propagation of changes in space time itself is what gives light its perceived velocity. | [
"Current commonly accepted physical theories imply or assume the photon to be strictly massless. If the photon is not a strictly massless particle, it would not move at the exact speed of light, \"c\", in vacuum. Its speed would be lower and depend on its frequency. Relativity would be unaffected by this; the so-ca... |
Why does conservation of momentum *have* to happen? | Ah I *love* this question because the answer is so cool. Momentum is conserved because physics is the same under continuous space translations. What that means is if I take a physical system here (like a pendulum or whatever) and move it x feet to the left, it will behave exactly the same way. Because of this fact momentum is conserved. Crazy right?
This is a specific case of Noether's theorem that says for any (continuous) symmetry of a physical system (ie a Lagrangian formulation of some specific mechanics), for these symmetries is an associated conserved charge (or current). For translation symmetry, the conserved quantity is momentum. For *time* translation symmetry, the conserved quantity is energy. For rotation symmetry, angular momentum. For "gauge invariance" electric charge. | [
"Conservation of momentum is a mathematical consequence of the homogeneity (shift symmetry) of space (position in space is the canonical conjugate quantity to momentum). That is, conservation of momentum is a consequence of the fact that the laws of physics do not depend on position; this is a special case of Noeth... |
Did the Soviet space program utilize German scientists like the American one did? | Yes, they did. Specifically there was [Operation Osoaviakhim](_URL_0_), which sought to recruit (mostly voluntarily) veterans of the German rocket program in the Soviet occupation zone. One of the more notable ones was [Helmut Gröttrup](_URL_1_), who had created the guidance system for the V-2.
They did not manage to recruit as many of the main people as the Americans did with Operation Paperclip, but on the other hand the Soviets acquired more rockets and related equipment, since the main facilities (Peenemünde, Mittelwerk) were located in the Soviet zone.
| [
"As Allied forces advanced during World War II, both the American and Russian forces searched for top German scientists who could be claimed as spoils for their country. The American effort to bring home German rocket technology in Operation Paperclip, and the bringing of German rocket scientist Wernher von Braun (... |
how are property lines decided and recorded for residential purchases? | Property lines are drawn when the area is first developed. If the area was first developed in modern times, it would have been split up into individual parcels and each parcel's lines would have been drawn quite precisely. If it was first developed a long time ago, there may be some uncertainty in the lines and records of usage can be necessary to determine who owns a particular piece of land.
The details of how they're recorded vary depending on the jurisdiction, but there's usually a governmental office that is in charge of recording property lines. In England and Wales, for instance, it's HM Land Registry. | [
"Residences can be classified by and how they are connected to neighbouring residences and land. Different types of housing tenure can be used for the same physical type. For example, connected residences might be owned by a single entity and leased out, or owned separately with an agreement covering the relationsh... |
What method of shuffling will most efficiently randomize a deck of cards? (and related questions) | Check out [Proofs From The Book](_URL_1_) by Aigner & Ziegler, Chapter 28. It's based on some work by mathemagician [Persi Diaconis](_URL_0_).
Essentially, you want to consider a process of shuffling the deck, like just taking the top card off and inserting it at random, or doing a perfect riffle shuffle with two halves of the deck. You can then consider how likely any possible shuffling of the deck would be after executing this process. Ideally, *any* shuffling of the deck should be equally likely as any other, so you want to know how accurately your process matches the "uniform probability distribution" (where all shufflings are equally likely). There's a way to mathematically express how "far away" your shuffling process is from picking a shuffling uniformly at random. This is what the chapter in Aigner & Ziegler discusses.
So, to answer #1: No, you can't just look at two decks of cards and say one was "shuffled better" than the other. We're actually looking at a particular *way* of shuffling cards and seeing how well the set of outcomes of that process, and their corresponding probabilities of resulting from that process, match the uniform distribution. Now, in a sense, setting the uniform distribution as the goal was an arbitrary choice; any other probability distribution could have been used, but our intuition wants the world to be such that any ordering of the deck is equally likely, so that's what we use.
To answer #2: I'm not sure ... You could follow the kind of analysis they do in that chapter and see how it shakes out. My intuition tells me, though, that you'll want to use a # of piles that does not divide 100. This prevents "cycling" of the deck. (For instance, if you make 10 piles of 10 cards each, and stack them up in order, repeating this step just twice will bring you back to where you started.)
I can't say which choice will make it "more random" "more quickly". Do you mean "speed" to be defined by "the fewest number of steps *required* to *guarantee* a certain level of randomness"? Or by "the most random shuffling produceable in a fixed number of steps"?
These are all difficult questions, but rest assured that there actually *is* mathematics there to investigate and answer them! | [
"Poor shuffling methods can make the order of cards in the deck easier to predict and the cards could have been inadvertently or intentionally marked and manipulated. In his experiments, J. B. Rhine first shuffled the cards by hand but later decided to use a machine for shuffling.\n",
"Shuffling is the process of... |
What are the fundamentals of Esperanto? Why was it created? Did any nation endorse/use it? Why did it fail? | There was an attempt to make Esperanto the language of Neutral Moresnet.
_URL_0_ | [
"Launched in 1887 as a project for an auxiliary language for international communication and quickly developed into a rich living language in its own right, Esperanto has worked for more than a century to connect people across language and culture barriers. Meanwhile, the objectives of its speakers have not lost im... |
If a young child is the recipient of an organ transplant, are they expected to be on Immunosuppressant drugs for life or is it possible that, atleast some organs, can be "replaced" on the cellular level in a ship of theseus sense? | Patients who receive an organ transplant can gain immune tolerance to their graft, referred to as "operational tolerance". Operational tolerance [can occur spontaneously](_URL_0_), but [it's quite rare](_URL_2_). Inducing operation tolerance with a specific medical procedure [is something of a holy grail for transplant research](_URL_1_), it'd be a game-changer for organ transplants. All the suggested procedures are still very experimental.
I think any organ would have far too large a mass to be entirely replaced by recipient cells, but certainly over time there won't be a distinct line between which parts of the organ contain donor DNA and which parts contain host DNA. The recipient will be what we call a 'genetic chimera' for the rest of their life. That is, they will contain two different sets of DNA.
I suppose it's possible that a child could be more likely to become operationally tolerant than an adult, but I can't find any studies that suggest this or disprove it.
Some of the latest research suggests that transplants of [some types](_URL_3_) of immune cell can help induce operational tolerance.
& #x200B;
edit: made links more distinct
edit edit: this is cool! [This study from a few years ago](_URL_4_) suggested that the presence of certain types of immune cell and molecules carried on them could indicate a child liver transplant recipient had achieved operational tolerance. | [
"Because very young children (generally under 12 months, but often as old as 24 months) do not have a well-developed immune system, it is possible for them to receive organs from otherwise incompatible donors. This is known as ABO-incompatible (ABOi) transplantation. Graft survival and patient mortality is approxim... |
Will our sun eventually die, and take us with it? | sort of.
Our son will not "die out" instead it will enter the RED GIANT phase of its life and expand outward. This could cause the earth to become engulfed in the expanding sun. If it doesn't engulf the earth completely it will very much close the gap between the earth and the sun's orbit which will bombard the earth with UV radiation and burn all life on the crust to a crisp.
This won't happen for a few billion years though. | [
"Life on Earth is dependent on the Sun's light and heat in order to survive, but our Sun won't live forever and eventually it will die one day. However, the Sun's death will not happen for billions of years. What if the Sun started aging rapidly at an accelerated rate?\n",
"Dr. Research continues, telling how sci... |
What are ten scientific facts that you feel everyone should know? | I cannot represent all sciences as a biologist, but I think one thing is very important for everyone to understand, evolution is a concrete scientific theory, where are there are really no other viable alternative hypotheses. We can demonstrate it with selection experiments in the lab, we apply the concept to antibiotic resistance in bacteria, the fossil record supports it, as well as the fact that all life operates on the central dogma of biology (RNA-DNA-Protein). Also, one more thing, evolution does not mean "progression." Evolution is simply genetic change over time, which can lead to an increase or reduction in complexity depending on which is more fit. Best example is parasitic worms, they lack much of the abilities their free-living cousins have, but they don't need it for their life history, so we've seen a reduction in overall complexity in such taxa. | [
"That's what's fun about it. We're breaking down barriers and finding things. That's what science is all about: new discovery. ... There's nothing that we have done or have demonstrated that doesn't have good science behind it. Skeptics be damned.\n",
"I would teach the world that science is the best way to under... |
how to blind people write? | Braille typewriters. [Here](_URL_0_) is a video describing how they work. That guy answers lots of questions about the blind btw, worth watching. | [
"For the blind, there are books in braille, audio-books, and text-to-speech computer programs, machines and e-book readers. Low vision people can make use of these tools as well as large-print reading materials and e-book readers that provide large font sizes.\n",
"The earliest systematic attempt to provide a met... |
Given the recent refuge crisis in Europe, is there any historical precedent for such a quick migration in so short of time? | Considering that around 1 million refugees and migrants entered Europe this year, yes, there is such precedent.
Between 1944 and 1950, following the offensive of Red Army, and Jalta, Teheran and Potsdam agreements, 13 to 16 millions ethnic Germans from Eastern and Central Europe had fled or been expelled to the Germany mainly from USSR, Poland, Czech Republic, Hungary, Yugoslavia and Romania. Another millions of people were relocated due to post-war geopolitical changes, i.e. 1,5 million Poles were deported from territories that used to be Poland and became USSR, to the territories that used to be Germany and became Poland etc.
It's really hard to give exact numbers here, considering what the situation was back then, but I think we can safely assume that about 20 million people permanently migrated from/to/within Central and Eastern Europe in the aftermath of WW2. | [
"Some scholars, among them Wolfgang Kimmig and P. Bosch-Gimpera have postulated a Europe-wide wave of migrations. The so-called Dorian invasion of Greece was placed in this context as well (although more recent evidence suggests that the Dorians moved in 1100 BC into a post Mycenaean vacuum, rather than precipitati... |
why do people appeal to the public about climate change and not campaigns for companies to change? | > Companies can be shifted by laws for example
and the people who pass the laws that regulate the companies are elected by the public. People appeal to the public on climate change issues because they are the relevant actors in any debate about climate change. People, individually, are investors, voters, and, lest we forget, carbon emitters themselves. | [
"Businesses take action on climate change for several reasons. Action improves corporate image and better aligns corporate actions with the environmental interests of owners, employees, suppliers, and customers. Action also occurs to reduce costs, increase return on investments, and to reduce dependency on uncontro... |
Why are imaginary friends so common in children? Is there something specific about the brain of a young child that causes these illusions? | Related question: Are imaginary friends really that common? I live in the netherlands and I had never heard about imaginary friends until I started watching american tv shows. My siblings and I played with dolls and stuffed animals all the time, but that seems different from the *persistent characters* of imaginary friends. (Not to mention stuffed animals have a physical aspect absent in imaginary friends). | [
"Other professionals such as Marjorie Taylor feel imaginary friends are common among school-age children and are part of normal social-cognitive development. Part of the reason people believed children gave up imaginary companions earlier than has been observed is related to Piaget's stages of cognitive development... |
If a planet in our solar system was impacted by a huge asteroid tomorrow, how long would it take for us to discover that, and would we be affected in any way on Earth? | Comet Shoemaker–Levy 9 (formally designated D/1993 F2) was a comet that broke apart in July 1992 and collided with Jupiter in July 1994, it caused explosions in the atmosphere visible by earth based telescopes. But Jupiter is so massive that something like this doesn't alter its orbit or cause any effects to the earth. Occasionally a smaller rocky planet is hit and this can cause fragment of the crust of the planet to be ejected at speeds that put them into interplanetary space. These fragments can then fall to earth in the form of meteors in turn causing craters on earth if the where significantly large.
As for how long between collision on mars and fragments reaching earth, it may take millions of years. | [
"More than 1M asteroids have the potential to impact Earth and through all the available telescopes worldwide, we have discovered only about one percent. The 100X Declaration calls for increasing the asteroid discovery rate to 100,000 (or 100x) per year within the next 10 years. “The more we learn about asteroid im... |
what are the financial dynamics that allow pacquiao/mayweather to make 100 mil for one fight, when the highest paid players in the most popular sport (nfl) take home 20 mil for the whole season? | The simplest way I could think about it is like this.. Your NFL team might generate 20 boxes of cookies over the course of a season, but the cookies in those boxes have to be split between 60+ players (roster and practice players) and a lot of staff members. There are also years in which the players can only take home a certain amount of cookies because of a cookie cap.
This fight might only generate 10 boxes of cookies, but all of those cookies are being split between 2 people. There is also no cap to how many cookies they can take home with them.
Nevada also has no cookie income tax, which means what they get more or less is what they can take home with them. Most other states have a cookie tax, so an NFL player does not get full value from their cookie contract.
edit: I'm surprised so many people liked my explanation. Just keep in mind that there is obviously a lot more that goes into the finances of how much money (I mean cookies) they will take home, but I tried to keep it as simple as possible since that is what this reddit is designed for. | [
"Interest in the lower weight divisions further increased with the possibility of a superfight between two of the current best fighters in the world, Manny Pacquiao and Floyd Mayweather, Jr. Experts predicted this would break current pay-per-view records, due to the tremendous public demand for the fight. Long nego... |
why do we awww everytime we see a baby animal, regardless if its a dog, cat, snake or even moose? | "...even moose." Wtf is that supposed to imply? Shitting on the glorious moose. Not cool man. Not cool. | [
" The fear of animals most often occurs in the third year of life. In some cases, the fear has logical origins such as a traumatic experience with a large seemly furious dog. In others however, the fear is less rational. When a child fears small seemingly harmless animals like bunny rabbits and kittens, it is often... |
Were there any forms of life that went completely extinct? What were they like in comparison to lifeforms we see on Earth today? (plants, animals, fungi, protists, etc...) | What do you mean by 'form' exactly? Clearly many *species* have gone extinct so are you talking about something more like body forms and structures (morphology) or larger groupings of species (taxa /taxonomy)? There is a great variety of forms in invertebrates, so drawing a distinct line between various body shape categories can get tricky. | [
"Life form (also, life-form and lifeform) – entity that is living, such as plants (flora) and animals (fauna). It is estimated that more than 99% of all species that ever existed on Earth, amounting to over five billion species, are extinct.\n",
"The groups that survived suffered extremely heavy losses of species... |
Who was the President, or the equivalent, from 1776 to 1789? | There was no executive branch under the Articles of Confederation. There was just a legislative branch consisting of the unicameral Continental (later Confederation) Congress. There was an annually-chosen position called "President of the Congress," but all he did was "preside." He had no special authority.
Point of trivia: The first guy to hold this position was named John Hanson. On certain Black nationalist websites, you will find claims that not only was he the first "president of the US," but that he was Black (or "a moor"). This misconception originates from the fact that another guy named John Hanson was a Liberian senator in the 1850s. You will find photographs of this John Hanson labeled as those of the first Black President of the United States. A lot of African Americans (like Prince, for example) are therefore wedded to the erroneous "hidden history" of the American presidents who supposedly preceded Washington. | [
"John Adams (October 30, 1735 – July 4, 1826) was an American statesman, attorney, diplomat, writer, and Founding Father who served as the second president of the United States from 1797 to 1801. Before his presidency, he was a leader of the American Revolution that achieved independence from Great Britain and serv... |
How did Europeans first react when they found out that Islam had spread all the way to Indonesia? | There are 3 main parts of this question
The first is: "When did europeans find out that there were muslims in Indonesia?"
The second is: "When did they find out the extent of muslim presence in the area?"
And finally: "What was their reaction over it?"
As for the first, the answer is murky. Indonesia was where much of the spices that came into Europe ultimately came from, and for several centuries that trade was for the most part controlled by the muslim world. Muslim traders were present in indonesia since at least the 8th century, and it was common knowledge among european traders (particularly venice and genoa) that muslim traders traveled from "somewhere to the east" and brought back spices. So even if they had no first hand accounts, it's not unreasonable to say that europeans were aware that there was "some" muslim presence in india, indonesia however was a virtual unknown, when Pero da covilhã visited Calecut in the 1480's he was surprised to discover that a lot of the spices heading west, actually came from some place further east, carried by muslim merchants.
The extent of muslim presence in the region however was unknown until after the Portuguese reached india in 1498. Up until that time, the portuguese expeditions to india and ethiopia, looking for the mythical Prestor John had been unsucessful in transmiting information back to Lisbon. Some expeditions didn't manage to get past muslim controlled areas like egypt, and others, though they suceeded in going to india and ethiopia, like the [voyages of afonso Paiva and Pero da Covilhã](_URL_0_) did not suceed in sending information back to Portugal.
It was only in 1511 with the conquest of Malacca that the portuguese would have better knowledge of the extent of muslim presence in indonesia. Up until then, it was believed (for the 10 or so years where the existence of indonesia was known to the portuguese) that the muslim presence was similar to what they experienced india, that is, a majority non-muslim population with some muslim traders or rulers.
As for the reaction of the Portuguese, there really wasn't much. Malacca was taken, and a few other forts were built in the spice islands, from where they could control the trade, and for the most part the strategy of getting a few forts from where to conduct trade, installing local kings friendly to them, and rellying on their naval power, thereby "replacing" the muslims role in the spice trade, was continued.
**TLDR** They basically said "huh" and carried on with their plans | [
"The history of arrival and spread of Islam in Indonesia is unclear. One theory states it arrived directly from Arabia before the 9th century, while another credits Sufi merchants and preachers for bringing Islam to Indonesian islands in the 12th or 13th century either from Gujarat in India or directly from the Mid... |
why is ocean life profoundly more diverse than freshwater life? | The oceans are much larger, with much more variable conditions.
Freshwater life is generally restricted to shallow depths, relatively stable temperatures, and small size.
Oceans are huge and have all sorts of conditions:. Pressures can vary from atmospheric all the way to a thousand times the atmospheric pressure (Marianas Trench). Temperatures can range from below freezing in the Arctic Ocean to over 400 Celsius (underwater hydro-thermal vents). More varied conditions mean that there are more, different niches that organisms can fill to survive, which allows very different organisms to survive. | [
"In contrast to the terrestrial and coastal ecosystems of the islands, the sea itself has a relatively low biodiversity. The reason for this is the brackish nature of the water. The salinity is only 0.6% in the Archipelago. The salinity has also varied greatly during the past, making it difficult for species to ada... |
Can our atmosphere vibrate and produce sound? | Sound is vibration of the atmosphere (or some other substance), so the answer is yes.
I suspect that you need to elaborate on your question, though. | [
"As a signal perceived by one of the major senses, sound is used by many species for detecting danger, navigation, predation, and communication. Earth's atmosphere, water, and virtually any physical phenomenon, such as fire, rain, wind, surf, or earthquake, produces (and is characterized by) its unique sounds. Many... |
why does a high ratio differential mean higher torque? | Basically when you short gear you’re losing potential top end speed for that boost off the line
You go through the gears faster with the same amount of power.
Think of it this way if you have a 0-100 of say 8 seconds, with a potential (not speed controlled limit) of 150 with stock gearing. Now if we short gear that vehicle your 0-100 will go down let’s just say to 7 seconds. But your top end max may drop to 130. And vice versa. | [
"Along with the multiplication of torque, there is a decrease in rotational speed of the output shaft compared to the input shaft. This decrease in speed is inversely proportional to the increase in torque. For example, a torque multiplier with a rating of 3:1 will turn its output shaft with three times the torque,... |
we keep hearing about how america "allegedly" goes to war for oil. if that is true, how does it work? they can't just drill for oil and transport it across the globe without anyone noticing! | The argument is that the US only gets their military involved in human rights issues when their access to cheap oil is being threatened. | [
"The oil pipelines are a frequent target of extortion and bombing campaigns by the National Liberation Army (ELN) and, more recently, the Revolutionary Armed Forces of Colombia (FARC). The bombings, which have occurred on average once every 5 days, have caused substantial environmental damage, often in fragile rain... |
how can east-timor (timor-leste) use the us dollar as its official currency, despite having no ties to the us? | The simplest part of this is that the government will accept payment of taxes in US dollars. That will usually be enough to get people using whatever the government takes for tax payments. Especially if nobody's printing anything else.
People in East Timor, and the government, can buy and sell U.S. dollars like anyone else. The US doesn't really have any interest in stopping them from doing so, and I'm not sure if they could if they tried.
For a very young country like East Timor, especially given the fragile state of its economy, there's some real benefits to using dollars as their currency: you don't have to ride the rocky currents of inflation and deflation as the markets try to figure out what the heck your money is actually worth. They can get outside lenders more easily, who know they'll be paid back in dollars, not a local currency that could have a very different value in ten years.
It's not without risk, though: American monetary policy does not consider the needs of East Timor, and so the US could tighten up the supply of dollars at a time when Timor needs a looser policy, or vice versa.
| [
"In 1975, Portuguese Timor was invaded by Indonesia, and Indonesian currency was introduced. When this territory was established as an independent state in 2002, the US dollar was made the official currency. The US dollar was also descended from the Spanish pieces of eight but it broke parity with the silver dollar... |
Could the ISS cast a shadow on the moon during a lunar eclipse? | Technically, if its in the right spot, it would block some light, but it's far too small and far from the moon for us to notice any difference. The moon is far beyond the edge of the ISS's solar umbra, and thus it's shadow would be blurred into imperceptibility. | [
"The Earth bound portion of the flight coincided with a lunar eclipse. This occurs when the Moon passes through the shadow of the Earth. The crew was instructed to photograph it but due to the hand-held nature of the cameras and the length of the exposures, most of the photos were blurred. Instruments on the lunar ... |
could someone please explain some of the most common reddit abbreviations? | IQTMPOA
I've quietly taken my pants off again. | [
"Abbreviations are popular across different cultures, including countries like Japan, China, France, Portugal, etc., and are used according to the particular language the Internet users speak. Significantly, this same style of slang creation is also found in non-alphabetical languages as, for example, a form of \"e... |
question about energy and space. | We do not orbit around the center of the universe. The universe has no center. I think you might have meant the galaxy? If thats the case than it goes like this. The galaxy formed out of a giant cloud of gas. Gravity slowly started pulling it together. It started speeding up until all of the gas in the cloud was falling very fast into its center of gravity. For science reasons beyond the scope of ELI5, the universe likes to make rotating disks. All of the kinetic energy that came from all of that falling gas became rotational energy, which is why the galaxy spins (orbits the center of the galaxy) | [
"Potential energy is associated with forces that act on a body in a way that the total work done by these forces on the body depends only on the initial and final positions of the body in space. These forces, that are called \"conservative forces\", can be represented at every point in space by vectors expressed as... |
how can a bunch of text characters crash a ps4? | Crashes typically happen when a program is caused to enter a state which is unexpected by the programmers, resulting in incorrect behavior such as infinite loops or the attempt to execute instructions which cannot be performed.
In the case of a message causing a system to crash it might be due to how certain kinds of text are produced. Different languages use different characters which are stored in packages. When a message is received it contains instructions on what packages of characters are to be loaded so the message can be displayed, and it is possible that there is an error somewhere in loading one of those packages where perhaps it does not exist, or causes other problems.
For example there are some languages which attach certain symbols to other characters, such as above or below them, to modify their meaning. The character packages contain instructions for how a symbol can be attached to another character, and sometimes you can even attach more than one symbol to a character, or nest them so a character has a symbol attached which itself has a symbol attached. A malicious user might then craft a message that has thousands of symbols attached to one character which results in the system trying to display something which the programmers never anticipated would be attempted, leading to unexpected behavior and a crash. | [
"Some computer programs, such as \"StepMania\" and BBC's \"Bamzooki\", also crash to desktop if in full-screen, but displays the error in a separate window when the user has returned to the desktop. Crashes are usually caused by website failure or system failure.\n",
"If in game play two cars crash, and there's a... |
Do metals (such as iron) rust faster in running water or in a stagnant pool? | Running water. At the hypolimnion of a lake (bottom), water hardly moves, and only does so during fall or spring turnover.
An iron bar will rust quicker in a stream because the water molecules are moving quicker, and this speeds up oxidation in the process. Reactions depend on collisions, and that same idea comes into play here. Water is also colder at the bottom, which makes the reaction slower in a lake vs. a shallow stream.
You're right in that it also has to do with the level of dissolved oxygen, as there is hardly any at the bottom of a typical lake (it varies from body of water to body of water as well as season to season.)
So, in summary: oxidation of iron will occur quicker in a body of moving water versus a body of stagnant water because of temperature, molecular velocity, and dissolved oxygen levels. | [
"Special \"weathering steel\" alloys such as Cor-Ten rust at a much slower rate than normal, because the rust adheres to the surface of the metal in a protective layer. Designs using this material must include measures that avoid worst-case exposures, since the material still continues to rust slowly even under nea... |
capitalism and socialism; and pros and cons of both. | Capitalism: a system of buying and selling things (goods and also services) where the price of everything is determined by the people or companies that are making or doing it. The companies have to make sure their prices are low enough so people will buy, but also high enough so they can make money. This is called "market driven" economics, because the market (that is, the combination of buyers and sellers) is thought to determine the price. Charge too much, nobody buys, charge too little, you go broke, hopefully you find the sweet spot.
Capitalism is good because it encourages people to come up with new ideas that they will try to sell for money. It also encourages companies to try to make their things as cheaply as possible so they can sell more.
Capitalism has problems too. Because the cost of a product often decides if it succeeds, things that are good ideas but are expensive may not catch on (solar cells, electric cars, etc.). Other times, the cost of a product may not really show how much it is REALLY costing, by which I mean things like pollution and use of limited resources. Pollution is what's called an externality. You make a hat that sells for $10, but actually the pollution caused by the hat factory will end up costing someone $100 in damage to their water or forest or lungs. Capitalism can not always react quickly enough to make sure everything is safe or actually a good idea.
Socialism: Means different things to different people, but let's talk about how it applies to money and buying/selling things. In capitalism, people are mostly free to buy/sell/make whatever as long as they have the money or the means to make money off of it. In socialism, the government decides or helps to decide the cost of certain goods/services and may even decide how much of a product will be made. This is in attempt to increase the overall happiness, health, and prosperity of its people.
When you hear about "socialized" items in the US or European countries, it's often healthcare. Socialized healthcare means that the government of a country provides most of its people with medical services with money from taxes. The government decided it is important, so the government pays the bill. In America's capitalist system, people have to pay for medical service or pay for insurance to do so; the government doesn't usually help or decide prices.
Socialist markets are good because they can help make sure everyone has what they need, especially important stuff like medicine. The government can help fix prices low or even give everyone what they ask for (within reason). They can encourage people to buy things that are good for them, and prevent them from buying things that might hurt them.
Socialism has problems because it can be hard for a government to decide exactly what everyone in the country needs, and if they get it wrong either money will be wasted or people will not have enough. Also, there might be something that only a few people want but won't ever be able to find. Plus, if the government decides that one product is good, the people who make/do it don't have a lot of reason to make it better ("My shoe factory is paid by government to make bad shoes, but what do I care? I get paid and don't have to work hard to make them better!")
| [
"Socialism is a range of economic and social systems characterised by social ownership of the means of production and workers' self-management, as well as the political theories and movements associated with them. Social ownership can be public, collective or cooperative ownership, or citizen ownership of equity. T... |
How is GPS so accurate? How is it able to tell me where I am within a few meters when the satellites are thousands of miles in space? How do they correct for minor drifts due to gravitational inconsistencies? | GPS satellites work essentially by triangulating your position from several satellites in orbit. As a first approximation, one satellite can give you your position on a sphere around the satellite. Two can give you your position on the circle that defines the intersection of the two spheres around the two satellites. Three gives you your position as one of two points on that circle. Assuming you are near the Earth and not several thousand miles in space narrows that point down to one place on (or near) Earth. (In fact, you almost always need 4 satellites minimum, because due to the information that GPS satellites transmit, you need to know a rather precise time to get any sort of accuracy. The 4th satellite allows you to determine your time to a far greater precision than a quartz oscillator).
So how does this triangulation work? Each satellite is constantly streaming information about itself: a unique identifier, its current orbit, and a time stamp for when the information is sent (the time stamp is very precise; each GPS satellite has an atomic clock in it. In fact, the atomic clock is one of the single most important features of the satellites). The orbit changes pretty slowly; the GPS belt is thousands of miles in space precisely to limit perturbations from things like Earth's second and higher order spherical harmonics (fancy words for non-spherical gravity) and drag. So, for now, we'll say that the satellites are in a very easily predictable orbit that doesn't change (it does change a little, but over the course of a few hours, the changes are vanishingly small). Knowing the satellite's orbit and the time (both transmitted by the satellite) means you know exactly where the satellite was in space when it streamed the information about itself. If you also happen to know the precise time when you receive the information from the satellite, you can calculate how far away the satellite is (since you know the speed of light). You now have that sphere defined I mentioned earlier. Repeat three times for three satellites to give you a pretty exact position. The fourth satellite lets you figure out the time, so you don't have to have an atomic clock on you at all times.
So how about errors? Well, you can see that precise determination of your position by GPS requires a very good estimate of the orbit of the satellite - you *need* to know where the satellite was in space when it transmitted its time to you, or you really won't be able to get any useful information out of it. This is accomplished by constantly monitoring the orbits of the GPS satellites and sending them updated information about where they are. This is known as the GPS ground segment. A number of ground stations constantly monitor the GPS constellation and send the satellites updated parameters that define the orbit that the satellite is currently in. This information is sent out fairly often - I'm not sure of the exact time, but I think it's about once a week per satellite. GPS satellites can go about a month without an update from the ground before the orbit is perturbed enough to cause problems with accuracy.
Precise position also requires a very precise clock. The satellites are in space for years (a decade or more) before being replaced; if the clock drifts by a lot in that time, then the information they stream to the ground will be wrong, and you won't accurately know your distance from the satellite. This is solved by including a very accurate atomic clock on each satellite. GPS time is a fantastic source for syncing your clock to because the satellites have very good clocks on board. One of the more hidden uses of GPS is for precise calibration of clocks for systems that require fine timing.
Of course, there are still errors. So the last defense of GPS is simply more satellites. Each additional satellite can give you more confidence in your position. More satellites actually over constrain the problem, so in the real world, you need to use mathematical tricks to determine where you must be such that the (random) error from all the satellites you're seeing is minimized.
Note that the vast majority of these calculations are done in your GPS receiver. The only thing the satellites are sending out are its current orbit and a time stamp. | [
"Inconsistencies of atmospheric conditions affect the speed of the GPS signals as they pass through the Earth's atmosphere, especially the ionosphere. Correcting these errors is a significant challenge to improving GPS position accuracy. These effects are smallest when the satellite is directly overhead and become ... |
Is there a material that conducts heat well and can withstand the temperature of lava? | It sure is feasible. [Iceland's](_URL_0_) single largest method of producing power is geothermal. It is also how they get a lot of their (non-potable) hot water. | [
"Because lava usually cools and crystallizes rapidly, it is usually fine-grained. If the cooling has been so rapid as to prevent the formation of even small crystals after extrusion, the resulting rock may be mostly glass (such as the rock obsidian). If the cooling of the lava happened more slowly, the rock would b... |
why is religion still so big in a hyper-informed world? | The world is not hyper informed. Information is easily accessible, but this also makes *mis*information easily accessible. Basically, you can find a community of thousands that support any crazy belief you have.
This also drives people into more niche social groups. The fact that you can be in an online community of thousands of evangelicals only makes you *more* evangelical. | [
"Fewer and fewer people believe nowadays. It's possible that in a generation, there simply won’t be religion across Europe and large sections of North America, Australia, and Asia. That's not necessarily a problem. However, it is worth thinking about why people made up religion in the first place, and what we’re do... |
how does a satellites stay positioned on a geostationary orbital target that is not on the equator? | Geostationary orbits are only above the equator. Geosynchronous orbits are at the same distance but not necessarily in the plane of the equator.
Communications satellites are not necessarily geostationary or geosynchronous; if there are enough of them all at different orbits then they can cover most of the earth. | [
"When observed from the equator, geostationary satellites follow exactly the imaginary line of the Earth's equatorial plane on the celestial sphere (i.e. they follow the celestial equator). But when observed from other latitudes the fact that geostationary satellites are at a fixed altitude of 35,786 km (22,236 mi)... |
AITA for sending my men to attack the same river valley 11 times? | NTA, your name shall forever be remembered amongst the likes of Scipio, Caesar and Aetius. | [
"During an 1863 expedition from Camp Douglas, Utah to Cache Valley, the United States Army attacked a Shoshone village at the confluence of the Bear River and Beaver Creek (now Battle Creek) in what became known as the Bear River Massacre.\n",
"The plans were for the 600,000 man strong U.S.First Army to attack no... |
If money was no object, Could solar and wind power, as the technology exists now, replace all other power sources? How much land would be required? | Well, they could, in terms of the amount of energy. But you'd still need baseline power. You never know if the sun doesn't shine or if the wind stops, and you need a power source that can be adjusted to meet demands during day and night. Also, the price would fluctuate heavily based on weather. Not good.
What that baseline source should be is an open question. Hydro works well. If you had enough solar and wind power, you could do things like pump water into a basin with excess power (windy nights, for instance), and send it out again when it's needed. Or simply use hydro as usual. Other more or less renewable forms like geothermal or future nuclear could also work.
As to land usage, I don't have an answer. | [
"Like wind power, solar power is another newer energy source in the country. The first solar power projects in the country were established in 1978 by just a few researchers from public universities at the Solar Power Laboratory at the National University. Though still on a smaller scale and mostly privately owned,... |
how can people like ajit pai, who is trying to reverse the regulations that the fcc exists to create, come into power as the chairman of such an organization? | The President nominates someone. The Senate confirms them (or doesn't). That's pretty much the extent of it, although I suppose that if the FBI background check failed, that would also end the process.
Trump nominated a radio talk show host to be chief scientist of the Dept of Agriculture. And someone to be a federal judge who has never tried a case in a courtroom and was rated "not qualified" by the ABA. And where Obama's first Secretary of Energy was a Nobel Prize winning physicist, Trump picked Rick Perry, who famously wanted to eliminate the DOE.
Trump bashing aside, the reality is that the Senate is supposed to act as a check on Presidential nominations. If they fail to do their duty and rubber stamp unqualified nominees, there is literally no process in place to prevent this.
All Presidents have had some questionable nominees (Bush chose someone with NO relevant to lead FEMA, all presidents tend to choose political donors to field important Ambassador posts)
It used to be worse. Before the advent of the Civil Service system, almost ALL executive branch positions were filled as political favors (the "spoils" system). Garfield was assassinated by a disgruntled office-seeker who did not get the job he wanted. Garfield, ironically, was the first to introduce substantial Civil Service reform, and the law was signed by his successor.
And while I agree that Pai is a poor choice to head the FCC, "corrupt" is really not appropriate. | [
"In January 2017, newly inaugurated president Donald Trump designated Pai as FCC Chairman. In March 2017, Trump announced that he would renominate Pai to serve another five-year term (remaining Chairman of the FCC). Pai was confirmed by the U.S. Senate for an additional five-year term on October 2, 2017. Before his... |
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