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What military technology, if any, where the Japanese more advanced then the other countries during ww2? | You cannot really ignore ships for your question. Ships is one of the places where one of the best Japanese weapons of the war was deployed, the Type 93 "Long Lance" torpedo.
The type 93 had a heavier warhead, better range, and better speed than any other torpedo in the war. It gave Japanese light fleet element devas... |
How does a pregnant body "decide" when it's time to go into labor? | The body doesn't the baby does. When the baby starts to get cramped for space it gets stressed and releases the stress hormone cortisol. The cortisol from the baby then starts a cascade of events in the mother that leads to birth.
EDIT: sorry I'm a veterinary student. This is how a lot of other species initiate partur... |
Did Pearl Harbour have the same effect on Americans' perception of security as 9/11 did? | Sorta. It certainly put some American citizens of the mind that the Japanese were "the other", just like many Americans did regarding Muslims in the days and months(and until today, really) after 9/11.
Since 9/11 is within the past 20 years or so(which makes it verboten for discussion), I'll simply point out that t... |
Are there many cases of a 'food taster' actually consuming poison and dying on the spot? | For some reason, people seem to want to fill this thread with things they've heard, movie anecdotes, and statistics on the speed of various poisons. None of these things actually answers the question, which involves whether a food taster ever *actually consumed poison and died*. If you cannot answer the question, pleas... |
When the Mongols were poised to attack Europe, how aware was western Europe of the impending attack? | They were on the whole pretty unconcious of the threat. The only prior knowledge Europe had had of the Mongols came from garbled stories that Crusaders had heard about Mongol conquests in the East. As they had very little idea as to what was actually going on they came up with a distinctly distorted image. The rumors o... |
Did Henry VIII make divorce legal only for himself, or for the whole nation under the Church of England? | Just to make a distinction... Henry VIII never actually divorced any of his wives.
* Catherine's was an annulment. It was declared an invalid marriage due to her previous marriage to Henry's brother, Arthur.
* Anne Boylen's was an annulment. It was declared an invalid marriage due to her (supposedly) incestuous relati... |
if pain is your body's way of telling you to stop doing something, then why does exercise hurt? | Med student currently procrastinating from my dissertation on pain here. Pain is a signal warning you of potential damage. In the case of exercise, you are ripping muscle fibres among other things, hence it is painful. In a wider sense your body cannot tell if something will be good long term, only short term, this is ... |
Did ancient civilians get PTSD? What do we know of the psychological effects of war on noncombatants, and how they dealt with them? | *Content warning: mention of sexual violence, suicide, casual misogyny*
& nbsp;
PTSD is a label we use to describe a group of symptoms connected to trauma and moral injury. The label was created in the 1970s to get Vietnam veterans in the US the support and mental health treatment they needed. As such, it was origin... |
Did Ethiopians know much about the state of Christendom outside East Africa before regular contact with Portugal was established? | This is a difficult question to answer directly: we have basically no surviving manuscripts from the early/high medieval period in Ethiopia. This will change in a big way in the 13th-14th century, in conjunction with the flourishing of the Ethiopian state and a renaissance in its Church.
The Ethiopic Church is of cour... |
why is the ocean sometimes really dark, like in the north atlantic yet in some places a turquoise colour like in the caribbean or south pacific? | It’s because dead animals and plants sink in water. That might seem obvious, but it means that any nutrients in sea water are rapidly used up by animals and plants and when those organisms die they sink to the bottom taking the nutrients with them. The only way those lost nutrients can be replaced is if water from the ... |
When and how did 750 mL become the standard size for wine and liquor bottles? | Moderator note: This is an AskHistorians thread. We expect answers to be in-depth, comprehensive and, more to the point this time around, *actually answering the question the OP asked*.
So far, we have had to remove endless discussions about *where* 750 mL is a standard size, *whether* it is at all, what you call it,... |
why are astronaut's movements in space seemingly slow motion when there's no air/water resistance to slow them down? | There are a few reasons. Their suits are pressurized. The joints of these suits want to fully extend due to this pressure. This makes it difficult to move and do things, and reduces precision substantially. Not only this, but the suits are quite heavy, and have inertia to slow movements. Lastly, the astronauts do not h... |
why a company like nestlè can take water out of a state/province for $2.25 per million litres, only to sell it back at a profit. who is letting this happen? | This is an explanation not just for this specific case but for large companies in general. These companies create jobs, and will also be paying taxes on a myriad of things. Sometimes the government will therefore sweeten the pot by reducing certain costs, knowing full well that overall they and the community will benef... |
In ancient times, say for the Inca. What would happen if human sacrifice did not appease the Gods and relieve the drought? | **I. In which I question the underlying assumptions and chronology of your question**
First thing first, the Inca Empire had its heyday from the 15th to 16th Centuries CE, which is not "ancient." Second, the nature of Inca theology was not one that necessarily included a direct transactional relationship. Benson ([200... |
Why exactly did the Soviet Union go to war with Finland? Why were they so ill prepared? | > What did they seek to gain out of it?
Finland had been part of the Russian Empire (as a sort of pseudo-autonomous Grand Duchy, whose Grand Duke just happened to be the Tsar) until 1917 and, when Russia descended into revolution and civil war, so did Finland, only there the reds lost.
(Fun fact, this is why Finlan... |
How old is the oldest DNA/RNA that has been extracted? Is it the same as the molecules all living organisms have in their cells now? Did nucleic acids evolve or are they the same as they were when life began 4 billion years ago. | DNA will break down over time. The oldest DNA ever reliably recovered was a couple hundred thousand years old, so fantasies of recovering 100 million year old dinosaur DNA are not realistic.
Even in creatures that have stayed relatively unchanged over time (like crocodiles) their DNA continues to mutate and change sli... |
- why do public restrooms have automatic soap dispensers if you will wash your hands directly after applying the soap? | Perceived convince and portion control.
A huge problem for businesses is users who take way more of bathroom goods that they actually would need, wasting goods and leading to more frequent empty situations.
Automatic dispensers usually have some delay between dispensing portions of a product, making it more dif... |
How does the cold war 'communism' scare compare to today's 'war on terror'? | *Nothing is so irretrievably lost to a society as the sense of fear it felt about a grave danger that was subsequently coped with.* -- George Will.
Reddit's demographic skews young, and people here don't often have the experience to be able to compare the modern "war on terror" to the "war on communism." The truth of ... |
why do businesses build skyscrapers in cities when it would be much cheaper to build their offices further out where land is cheaper? | There are a lot of advantages to having an office in a central downtown area like this.
1) Free advertising
2) Good public transit/ease of access for employees
3) You can rent out unused floors and are likely to fill them as the space is in higher demand
4) Skyscrapers can be more efficient/more compact than wid... |
[META] This is one of the few subreddits that has maintained a high level of quality and professionalism over time, thank you. | The mods deserve a huge congratulations on this one as well. The flaired members are huge sources of content that is always well-thought out, well-sourced and comprehensive, but the mods take a *lot* of time to remove comments that are none of these things and just come from the average redditor. So great job mods on /... |
Are there any "dead" sports? Sports that were huge at one time but then stopped being played? | Chariot racing used to be very, very popular in the Roman and Byzantine empires. Here's a couple anecdotes:
* The highest-paid athlete in all of history was likely the charioteer [Gaius Appuleius Diocles](_URL_1_) (2nd century AD). He earned enough in his lifetime (about 15 billion in today's dollars) that he could ... |
Everyone knows about Roman slavery, and the Transanlantic Slave Trade. But how about slavery in Medieval times? | Many enslaved women in the late medieval Mediterranean were forced into work as wet nurses. This is an excerpt from a longer article I wrote on wet nursing in Latin Europe:
For enslaved women forced to serve as wet nurses, the situation was even more demeaning than that of the municipal nurses. Since 1179, canon law h... |
Are Sociopaths aware of their lack of empathy and other human emotions due to environmental observation of other people? | I've found one research project where researchers investigates self-insight amongst teens diagnosed as psychopaths and their parents opinions of them. Three was little agreement, teens weren't as aware of their callousness and unemotional traits as their parents were.
> Our findings revealed low levels of parent–chil... |
Do the contents of our blood have any affect on mosquitos after they drink it? Do drunk people make drunk mosquitos? | I think the answer is, "[we don't know](_URL_0_)," but it seems that mosquitoes are more attracted to drunk people, than sober people, and according to the article I linked fruit flies do get drunk, but have a high tolerance.
Same article also says, "Any liquid other than blood is diverted first to a separate digesti... |
You are a fairly well-off Londoner in Victorian times. How would you "park" your horse-drawn carriage without it being stolen? Did someone have to stay with it at all times? | For a short visit like a social call, your driver (and possibly footmen) would stay with the horses outside. For a longer event, like a dinner party, ball or night at the theatre your carriage would drop you off, then return and collect you at a pre-arranged time, which is why grand formal invitations still say 'carria... |
the ISS is a pretty well closed system. Every astronaut has brought their own microbiome, do we know anything about what they leave behind and what survives? | [_URL_2_](_URL_2_)
[_URL_0_](_URL_0_)
& #x200B;
EDIT: Found the paper I describe below -- [_URL_1_](_URL_1_)
Going to space also makes bacteria much more resistant to antibiotics. I'm guessing that has something to do with gravity as well, with antibiotics ending up "walled in" by clumps of dead cells that then do... |
how do animals like ants and birds instinctually know how to build their dwellings/homes? | They have inherited the knowledge in their genes, but they learn through trial and error, at least that is what we assume. There's quite a lot we don't know about ourselves and nature, but that's why we keep studying.
They're really fascinating animals. We had a bird in our garden that made a square nest, for no reas... |
Which time period did drinking tavern/inns become a thing in Europe as depicted in fantasy stories such as LOTR? | * [Medieval Pubs: Ireland](_URL_2_) by /u/gothwalk
* [I'm a peasant visiting a 14th century alehouse. How would I be charged for my drinks and how easily could I skip the bill?](_URL_0_) by /u/sunagainstgold
* [What wrong ideas about medieval Europe might one get from popular works of "medieval fantasy"?](_URL_1_) by... |
Can fish live (or at least breathe) in liquids that are not water? For example milk | No. Fish can’t even live in water that has the wrong amount of salt or dissolved oxygen in it. Putting a fish in a liquid other than the correct water would be like putting a human in the Venus atmosphere. Sure it’s “air” but the concentration of oxygen, nitrogen, CO2, etc are all wrong. Every animal, especially fish, ... |
What happened to Roman soldiers who were non-fatally injured, but who couldn't keep up with the pace of the legion when marching? | Not to discourage any further answers but you'll probably enjoy
[You are a Roman solider marching a long distance. Your leg breaks for whatever reason; what happens?](_URL_0_)
[How likely would a Roman soldier be to survive injury on the battlefield?](_URL_1_)
By /u/Celebreth |
What did Medieval soldiers do during sieges waiting for the fort/castle/city to starve? | I can give you an idea of what a crusader army was doing and you may be surprised by how much activity was necessary to keep a besieging army in the field, even when it was static.
**Food and water**: Although we might think of those trapped within a city as being desperate for food, it was often the other way round i... |
If I were traveling at near the speed of light (enough to significantly slow time), would I be able to "think" normally? Would I be able to tell that time is slowing down? | As long as you were moving at a constant velocity, then nothing would appear "strange" to you. A key point of [special relativity](_URL_2_) is that the laws of physics work the same in any (i.e. non-accelerating) inertial frame of reference. So yes, if you have a spaceship that is moving *relative* to a planet, then th... |
Do the animals (mammals, mostly) that we keep as pets exhibit behavior that is akin to that of a human suffering from Stockholm Syndrome? | As /u/Nixie9 has already pointed out, definitely, without a doubt. That said, saying so is slightly problematic.
One of the most common mistakes people make when trying to understand animals and animal behavior is assigning human feelings and characteristics to them; personification of non-persons is always a little w... |
why do lips get chapped in cold weather compared to hot? doesn’t the hot air absorb the moisture more? | Hot air does make moisture move more, but that also includes nearby water sources, making the air more humid.
The higher water content of the warm air doesn't suck from your lips as much as the very dry cold air.
Plus, when it's warmer, you're sweating more, applying moisture more directly. |
why do employers ask to upload resume and also fill out employment history, school information, etc... that is already listed on the resume? | Not all resumes include all of the information they want. My resume hardly says anything about my schooling, and only lists my current position, as my prior employment was in different industries.
Resumes are always different, and the job seeker has a lot of wiggle room regarding what they can put on it. Some people a... |
To create artificial gravity in space, why cant the spaceship be rotated at high speeds generating centripetal forces that 'pull' the occupants to the edges? | > why isn't this ever talked of as a possibility?
It is! It's a really common sci-fi trope, for a start. Recently, there was a proposal put to NASA in 2011 for a spacecraft called [Nautilus-X](_URL_0_), which had with a big spinning wheel. I'm sure it's just one design of many over the decades.
Unfortunately, the oth... |
Is it more fuel efficient for a car to accelerate more before going up a hill or maintain a constant speed before and during the climb? | In order to maximize fuel efficiency, rather than keeping a constant speed, aim for a constant engine speed by looking at your tachometer (RPM gauge). Fuel efficiency is best at maximum torque, so keep your RPM's around 2500-3000 (the exact number isn't as important as keeping it constant) regardless of if you are goin... |
Why do abandoned buildings seem to decay so quickly when people live in buildings that are centuries old? | Buildings that are not abandoned are maintained. Wood is protected from rotting, iron and steel is shielded from the environment to slow down rusting, plants are prevented from growing and breaking apart concrete and mortar, etc.
Basically, most man-made structures are not designed to be able to withstand the harsh e... |
If we don't know the exact value for Pi, how can we know the exact area of a circle if that is 2(pi) Rad? | We *do* know the exact value of pi. It's... pi. You are most likely conflating "knowing an exact value" with "having a terminating or repeating decimal representation". A number that lacks the latter is no less exact than any other number. Also, we may compute the decimal representation of pi for an arbitrarily large n... |
How difficult was it to design Chess? Was there multiple, evolving versions of it? How did it spread across the globe like it has? | Chess was most likely created in modern-day India roughly 1500 years ago, where it was called "four members" (chaturanga), referring to the 4 parts of an army: cavalry, elephants, chariots, and infantry. The earliest rule sets are lost to time, but it looked similar to modern chess. It was played on an 8 by 8 board wit... |
In 1604 there was a supernova that caused a star to be bright enough to be seen during day time. How was this interpreted at the time? Did any figures or groups try to capitalise on it for political or spiritual influence? | Hopefully more people will be along to provide other perspectives!
Apparently, physican Baldassare Capra used the nova as an excuse to attack Galileo and make himself look better. Given the number of you who have heard of Galileo versus the number familiar with Capra, I think we can guess how *that* turned out.
There... |
Were any Jewish athletes who participated in the 1936 Berlin Olympics killed during the Holocaust? | Yes, there were many Jewish athletes from countries in Europe, America, and North Africa who competed. For example, Bronislaw Czech, from Poland, was a downhill skier who competed in the '28, '32, and '36 olympics. During the holocaust he was sent to Auschwitz, and died there after refusing to train German skiers.
So... |
what is so special about baking soda? why does it have such amazing properties for everything? | > how has something so awesome stayed so cheap also.
Baking soda is made from a reaction of easily obtainable items, so costs to produce are low. If I recall correctly, its carbon dioxide, salt and ammonia.
Some commodities stay low in price, regardless of their high demand and large scale production of an item, gen... |
When did Italians start identifying as Italian instead of Latin or Roman? When did they begin to see themselves as fundamentally different from the Romans in Constantinople? | That's a million euro question. The issue of Italian identity has been controversial and debated for a very long time. Italians themselves seem to be unsure: there are examples of Independence and Unification champions travelling to other regions and describing them as "different as Japan" and that was the Age of Natio... |
Is the Roman Catholoic tradition of canonizing saints connected to the Roman (pagan?) tradition of deifying state heroes? | Before Christianity was ever centered in Rome, it spread throughout the Middle East, made its way across the former Persian empire to India and traveled south, deep into Africa. Although Rome was the center of the Roman empire, Roman culture was not shared by large swathes of the ancient Christian world. However, the C... |
There are Glasses that make Colorblind People see colors. Do they work the other way around too? | The most common form of colorblindness is [to see red and green as the same color](_URL_3_).
Sometimes it's because the red or green cone cells are missing, but usually it's because [they respond to almost the same color light](_URL_1_) (vs [normal vision](_URL_2_))
How the glasses work is by blocking [colors betwee... |
How did Michel Ney, a competent commander his whole career, screw up so badly at Waterloo? | Michel Ney, *les brave des braves*, was a rather interesting character in the Napoleonic Wars. Being in the original class of the Marshalate, he was unique that he didn't serve directly under Napoleon nor was particularly famous in France as being a competent commander, rather he was known within the French army as a d... |
(nsfw) why is it that men "get back to their senses" after ejaculation? | [This comment](_URL_0_) summarizes it relatively simply. It comes down to the limbic system, which is a set of brain structures responsible for controlling instinct and mood. Basically, when you're that horny, some areas of your brain have less blood and oxygen going to them, and as soon as you ejaculate, the limbic sy... |
If a moderately well-off citizen of ancient Rome wanted to take his family on a vacation, what sort of options would be open to him? | not discouraging anyonen with specific information about vacation options in ancient Rome, but FYI there have been several questions about vacations in ye olde days. I've taken this opportunity to do a general roundup (with an eye to adding them to the "popular questions" wiki); I've indicated which ones include respon... |
Pretend I'm a fish and get swallowed whole by a shark... How long do I live inside the shark/what ultimately kills me? | > Most sharks swallow their food whole or bite it into relatively large pieces. Sharks have U-shaped stomachs that use very strong acids and enzymes to dissolve most of what is eaten.
Doesn't sound like a very long time.
Source: _URL_0_ |
Besides Solar, and Hydro, are we likely to develop a method of generating electricity that isn't ultimately steam turning a fan? | Maybe not forever, but for the foreseeable future... yeah probably. All of those things generate heat, and there are only so many things you can do with thermal energy. You can directly convert it to electricity via the [Seebeck effect](_URL_1_), as is used in [RTGs](_URL_4_), but it's extremely inefficient. The conver... |
why in some countries people just wipe but in some countries they use a bidet and wipe? | Just cultural anomalies. I live in England, and we bought a house recently which came with a bidet. This is unusual in the UK, and we don't use the bidet...we've discussed taking it out when we remodel the bathroom in a couple years, making room for a larger bath, perhaps.
#
However, I can objectively see why a bidet... |
If we can't put anymore transistors on a microchip because the transistors are physically too small, why don't we just make bigger microchips? | they can make them larger...but that wont make them faster. Think of it like this....you work downtown....you live within the city center...you commute to work. The city becomes increasingly crowded and people move further from the city center....and their commute to work is longer and longer the bigger the city gets. ... |
how do they make weed killer that they can spray on grass and plants that only kill weeds without hurting the grass or plants? | There are two major families of flowering plants, called dicots and monocots. There are a lot of subtle differences between them, but one of the easiest ways to tell is the [shape of the leaves](_URL_0_) EDIT: and the way the veins are arranged
Grasses and almost all grain crops, like corn, wheat, and rice, are monoco... |
why is it that sitting for extended periods can cause blood clots but laying down sleeping for 6-8 hours a night doesn’t? | When you sleep your blood does not have to flow upwards, your body is mostly straight and you are still moving alot in sleep. So If your leg is broken and you can't move a little your chance developing cloths is higher. That's why they give you shots in hospital every day. While sitting the legs aren't moved much, they... |
on old fashioned ships from the 1600s pirate times etc i’m guessing they had fires to keep warm how did they keep these safe and protect the wooden ship from burning? | In the age of sail, ship's cabins were poorly ventilated, and dozens (or even hundreds) of men would keep the cabin more than warm enough with their body heat alone when they were sleeping. When walking about the deck of the ship, warm clothing was about all that could be relied on.
Ships were extremely flammable, wit... |
How and why was the Polish-Lithuanian Commonwealth formed? What lead to its demise? | Poland and Lithuania had a personal union under Sigismund II. A personal union means that two countries share a monarchy, such as Austria-Hungary having the Empire of Austria and the Kingdom of Hungary as two separate entities, ruled by one person who was simultaneously the Emperor of Austria and King of Hungary.
Aro... |
why when we become self-aware of something, such as blinking, we have an increased urge to do it? | Take a second to think about blinking. Now that you’re thinking about it, you probably stopped blinking to see what would happen. In this time, you may have missed several blinks that would’ve happened naturally and not really even been noticed. Now, you’re brain is going to go “oh crap, I didn’t blink! Let me make up ... |
scientifically speaking, what determines the color a leaf will change to in the fall and do trees always change the same color year after year? | Well I don't remember too much about leaf senescence and pigments right now, but here is a quick answer to hold you over until someone comes along and corrects me.
Basically, leaves have colour because of pigments. Different pigments absorb different colours (wavelengths) of light. They also reflect other colours. Lea... |
Why does a standard computer keyboard have 12 function keys (F1 - F12)? | Holy guacamole, I can actually answer this one. But first we have to go back to mainframes...
Back in the days of yore, desktop computers weren't a thing. Instead, you'd have a keyboard and monitor connected to a terminal of one sort or another. There were two main categories: *character-oriented* terminals and *block... |
why when i'm trying to fall asleep do i begin reliving cringe-worthy moments in my past? | There are lots of reasons - one of the primary ones being that in our history as humans, avoiding pain was a much higher priority than seeking pleasure as pain. So it makes sense that our subconsciousness tends to focus on negatives rather than positives, especially as back when evolutionary pressure was at its highes... |
how come mammals’ fur doesn’t come in a wider array of colors like green, blue, pink or purple? | The only reason reptiles like snakes are brightly colored is to alert predators that they are poisonous. Birds are brightly colored to attract mates. Fish are brightly colored to attract mates and alert predators they are poisonous. Amphibians like frogs are brightly colored to alert predators they are poisonous.
Mamm... |
Is there any record of Joseph Stalin ever expressing any remorse for his executions, repressions, or for the death of his son Yakov? | I'm going to recommend you (or anyone else interested in this topic) read [*Stalin: The Court of the Red Tsar* by Simon Sebag Montefiore](_URL_0_).
The word "remorse" does not appear in that book.
However, "sorrow" does show up on page 525 of the 2007 edition:
> "Yet Stalin talked about their acquaintances murdere... |
Attention loyal citizens of AskHistorians, it is time to come pay homage to your New Mods! | I’m no longer the new guy! It’s like that Recess episode. I get my name back, the hazing ends, I don’t need to be Zhukov’s stool or fetch coffees, or any of the other things I was told are traditional. |
why i can buy a new tv for $300, new tablet for $500 but a new phone costs $700? | A new phone does not cost $700 dollars. *Certain* phones cost $700 dollars, just like there will also be high end TVs that cost $2000 dollars and low end phones that cost $30. And those high end phones cost that much because that is how much people are willing to pay in that market segment. |
What is the difference between modern day wine and its ancient (BC and first couple hundred years of AD) counterpart? | Here's a very interesting AMA from last month :
_URL_0_
Answers from /u/Queniden :
> * Reports of wine made in amphoras is that they are **much more oxidized** (sherry-like) than what we are used to now.
> * **Both wine and beer has changed tremendously in style over time.** Even over the last few decades. I... |
Why didn't the killer bees ever move any further north in the US? | Beekeeper here. Killer bees do, in fact, move further north, but the difference of climate and environment actually change the bees' behavior and they end up behaving just like a normal honeybee. I've moved bees from Texas to Colorado and have seen many hives get to Colorado and behave like killer bees, except after se... |
When was the last time a notable american publicly advocated for the institution of slavery? Did southerners stop bothering to ethically argue for it during reconstruction? | I feel like you might get better results if you rephrased the questions. The 13th Amendment banned slavery, so people who were clamoring for its return were just being nostalgic.
As far as last notable American advocating for slavery, does that include a Lost Cause narrative? I'm sure you can find examples of Strom T... |
I keep seeing people accusing /r/AskHistorians of being Marxist in nature, can someone help me explain why this isn't true? | As it states on [our rules page](_URL_5_): /r/Askhistorians is a forum that aims to provide serious, academic-level answers to questions about history. In line with that the mod team understands the core mission of this sub as educational outreach in the historic profession. Our main mission, our sense and purpose, is ... |
Does purposely letting my laptop 'drain' the battery actually help it last longer unplugged than keeping it charged when I can? | No. Lithium-ion batteries (almost certainly what's in your laptop) gain no advantage from being discharged fully before charging.
Older Ni-Cad batteries (and possibly also older NiMH batteries) suffered from a so-called 'memory-effect' that could give them less capacity if not fully discharged before charging, but eve... |
If you were to fall into a black hole, just as anyone watching would see your time slow down until you stop forever on the event horizon, would you in turn see the entire future of the universe pan out in front of you? If not, why does the mathematics not allow this reversal of perspective? | No.
* The premise is wrong. No one will see you stopping forever. This is a purely mathematical result. Yes, the intensity of light you expect far away will never reach exactly zero. But it will quickly become ridiculously low ( < 10^-10^100 ). You will quickly receive the last photon ever, afterwards the object has f... |
Is there a way of determining the boiling point of any(known) substance other than trying? | For a material we don't know the boiling point?
You can predict the melting point using [Lindemann's criterion](_URL_0_) (for crystalline solids) by looking at the how the vibrational frequency of atoms vary with temperature. At some temperature, the atoms could occupy the same space, so the material melts.
However, ... |
Jews were expelled and banned from England in 1290 by Edward I until Cromwell began to readmit them in 1655. Given medieval era Jews' roles as lenders and merchant bankers did their 366 year absence have any noticeable affect on the English economy? | After the expulsion of the Jews in the middle ages the vacuum was filled by Italian merchants, Lombard Street in the 'City of London' (the financial district of London) is named after Lombardy where many hailed from.
The laws against usury prevented them from charging interest on loans until 1546, when Henry VIII re... |
why can you "taste" certain foods after burping, even when it is hours later and you have eaten or drank several other types of food and beverages after eating the initial food? | Smell is a major component of how you"taste" foods. Food can stay in your stomach a long while, especially if you're having a hard time digesting it.
Gases from your stomach carry with it the smells of the food in your stomach when you burp. You smell it again, so recall the tasting of the food. |
Why do babies say double-syllable words like "mama" and "dada" when one syllable would seemingly be easier? | It depends on what stage of language development the kid is at.
As children age, they go through distinct stages of learning, and they acquire the ability to recognize, and later produce, words of increasing phonetic complexity.
For example, it's easier for a child to say a 'd' sound than it is to say a 'th' sound.... |
Will spiders use already formed webs that they have found (whether the web is from the same species or not) or do spiders only use webs that they themselves have made? | I did a bit of research, and I want to offer an expanded and more in depth answer.
As I mentioned in my first post, web building spiders tend to build and rebuild there webs. This is true, but not all web building spiders; some spiders, once the web is built, tend to just repair the web where it's damaged.
To answer ... |
when radio stations say they have 12 million listeners, how do they know? | [_URL_1_](_URL_0_)
There are basically two methods:
* Surveys. The company asks a representative sample of people "which radio shows did you hear last week"? A similar method is diaries, where each person in the survey keeps a list of every show they hear.
* People meters. Each person in the survey has a special mach... |
how the "helicopter effect" happens in a car when you have a window open. | Imagine the air entering your windows. It gets sucked in because you have compressed the air in front of you and it wants to expand. Nothing in nature is perfectly symmetrical so one side gets more pressure than the other for now. However, because of the shape of your car (it's not streamlined with your windows open... |
During the World Wars, did the female nurses face the risk of sexual violence from soldier of their own countries? | There is certainly much that can be said for other nations, but having written previously on the Red Army, I'll repost what I have written on that topic as regards women in uniform and sexual relations. Not just rape and sexual violence, but also consensual relationships. It also isn't solely about nurses, although to ... |
when you read that flu has killed otherwise healthy people, what are the symptoms that actually take them out? are they drowning in lung fluid or exhaustion from coughing, or what? | A few ways. The flu can cause intense inflammation in your lungs and you can die from respiratory failure. That's the most direct way (along with heart or organ failure, also brought on by inflammation).
But the flu can kill you by making you susceptible to other bad stuff, too, because your body is weak and slow... |
why do marvel movies (and other heavily cgi- and animation-based films) cost so much to produce? where do the hundreds of millions of dollars go to, exactly? | CG is very expensive. CG artists are specialists and in high demand. Making a big budget CG blockbuster like an Avengers film employs hundreds of them for years. The personnel costs alone are crazy.
Actually rendering all that CG also eats up a huge amount of time on very valuable, very powerful computers. |
How did the different knightly orders cope with the modernising world? (with the Teutonic knights and the Hospitallers surviving long after their crusading times were over) | Henry Sire recently published a book called *The Knights of Malta: A Modern Resurrection* about just this topic (for the Knights Hospitaller, at least).
A brief background: The Knights Hospitaller staged a centuries-long retreat from the Holy Land, ending up in Cyprus (as the Knights of Cyprus) and Rhodes (ditto), be... |
why aren't you allowed have contact with an organ donor for years after the transplant? | I'm actually in the middle of all my tests to donate one of my organs, so I had this conversation somewhat recently with my coordinator.
It depends on the particular hospital and program you are using, but you absolutely can have contact between donor and recipient if both agree to it. The initial contact is organize... |
how is it that we put salt in ice cream machines to make the ice colder, but we also put salt on our sidewalks and streets to melt the ice? | Because you're not making the ice colder in the ice cream machine. In both cases your goal is to make liquid water colder, but the reasons for wanting colder liquid water are different.
In the case of the ice cream maker, there's always at least a thin layer of liquid between the cream container and the solid ice, ... |
Would a child from 10,000 years ago fit in if raised from birth in today's society, 100,000 years? How far back could we go before we have a significant degradation of cognitive ability? | I think probably from about 200,000 - 100,000 years ago cognitvely, as this lines up with migrations out of Africa. However in terms of a decent immune system you are probably looking at about 10,000 - 7,000 years ago as this lines us with the first instances of livestock rearing by humans and therefore the development... |
Is this true? Did Britain really replace India's education system and caused the decline of social values? | This image does not appear to be accurate. I went and tried to look up the Parliamentary record for February 1835 and it seems that [Parliament was in fact not in session on the 2nd February 1835](_URL_2_). On the FAQs for the Parliamentary Archives [the question of Lord Macaulay's alleged speech is actually dealt with... |
Are the secret doors, complex puzzle locks, deadly traps, and other ancient mechanisms that we see in movies based in reality? | There are some very old stories about actual traps. One of the most famous is the claim that [the tomb of the Qin Emperor had crossbow traps](_URL_0_). At present excavation of what is strongly believed to be the site is ongoing but very slowly, due to among other issues extremely high mercury levels. I don't know of a... |
Why are elementary-aged students in the US knowingly taught a version of US History that middle and high schools have to completely contradict and reexplain? | I am not a historian per se, but I am a teacher, so hopefully I can answer this question in a way that the mods will allow to remain. If not, forgive me.
Teachers in all states of the United States are required by law to teach certain standards (standards may vary). I'm based in the state of Texas and we are required... |
what is the white stuff (i assume it's ice) that i always see falling off of space shuttles at take off and what does it do? | It's ice. It forms on the fuel tanks becauce the fuel is very cold. What does it do? It falls off.
Edit: Our benevolent overlords have required more details about the fuel and tank. Very well, but no peeking in this section if you are under five. The fuel consists of liquid hydrogen, along with a liquid oxy... |
why does placing a plastic bag over a credit card help a device read its magnetic stripe better? | The black rectangle on your card holds a number. Actually it's a set of numbers separated by delimiters, but that's not important. Just pretend it's one number.
If your card gets damaged, gaps appear in the electrical reading of the black strip, which means that inconsistencies appear in the number. That's no good;... |
why did russia decide in the late 1500's to attempt to conquer siberia - an unimaginably large & frigid territory - which would increase the size of its kingdom by ~17x? | The time of Russian territorial expansion was a time of colonialism for all the great powers of Europe. Russia was not well situated to become a maritime power like most of Western Europe, but it did have essentially exclusive access to "unclaimed" territory to its east. While Britain, France, Spain, Portugal, and the ... |
Has science now come to the certainty of 100% that an asteroid or meteor colliding with Earth was the cause of the dinosaur extinction? | It's a little more complicated than that. All dinosaur species didn't -go- extinct, as their decendants are still with us today, and many others went extinct long before the Chicxulub impact. But it is widely agreed that the mass extinction at the end of the cretaceous period was caused by the change in climate trigg... |
How do Olympiads keep breaking world records? Won't there come a point where they can be broken no longer? | Of course there *is* a limit, but the limit can be pushed further and further with the proper technology, diet and training. Maybe someone discovers a new technique for sprinting, or a better way to propel yourself at the start of the race. Or a new method of acceleration? Or perhaps someone discovers a diet that gives... |
We often hear of "killing the messenger," but how dangerous was it, really, to be a messenger bearing bad news or unwelcome demands in Classical or Medieval Europe/Near East/North Africa? | Follow up question: Did the "this is Sparta!!" scene actually happen? Did Leonidas actually kill Xerxes' messenger or was it just a heated argument that was glorified in the movie? In general, was it common for messengers to get killed when the message they brought would lead to a declaration of war? |
why is the body of a 400-lb person able to carry around 200 lbs extra day after day, but a healthy 200-lb person who weight trains extensively would be exhausted carrying 200 lbs for an hour? | A 400lb man's weight is centralized to his frame, spread throughout his entire body. There would probably be excess around his mid frame, which causes a lot of overweight men to have back problems.
because of this increase in mass, the overweight person has more blood with which to oxygenate his muscles, making it poss... |
Because of the curvature of the Earth, are nearby skyscrapers closer together at the base than they are at the top? | Yes.
If the two 100-floor buildings are one NYC block apart, which is 0.05 mile or 1/500000 of Earth's circumference, their 100th floors, which are .2 mile higher than their first floors, are going to be 2 * .2 mi * pi / 500000 further apart than their first floors, which comes out to .16 inches or 4 mm. |
Why is it that the American colonies with the highest Puritan populations are now the least religious and most liberal states in the country? | That's a fantastic question. I've also wondered about this myself. I'm very interested in how the Puritans, once the MOST conservative religion in Western countries, became the MOST liberal religions: Unitarians and Congregationalists.
The lesson here is that tribes of people and their practices and cultures can chan... |
"Prussian discipline" is a term that comes up quite a bit. In what ways was Prussian society more disciplinarian than other European cultures of the age? | Prussian discipline referred to both the state of Prussia and its inhabitants as well as the army. But it was used first for the army and then transferred to state - which is not really surprising given how highly militarized Prussia was. The French Marquis de Mirabeau (edit: I falsely attributed the quote to Voltaire,... |
Did ancient Roman women shave their legs, armpits, and/or pubic hair? What was considered the fashion vis-a-vis body hair for women of the ancient world? | Hello everyone,
In this thread, there have been a large number of incorrect, speculative, or otherwise disallowed comments, and as such, they were removed by the mod-team. Additionally, many have simply commented about the deleted comments, which serve to merely compound the issue. Please, before you attempt answer t... |
If I was to travel back to 12th century England, would we be able to easily understand each other's use of the English Language? | No, you would not be able to understand the language nor would you be understood. You would be hearing Middle English, and early Middle English at that (as the transition between Old English and Middle English happens around the 11th century). You might hear a word here or there, but the majority of the language would ... |
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