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cit44b | How do fans without blades work? | If you mean like the Dyson fanless fans, they have one big fan hidden in the base, that sucks in air from the holes, then pushes it all out of the 'fanless' section via a slot that runs along the edge | 18b4532f-d718-4de6-877f-d28d33a23a5b |
citcqa | Why is India and Europe linked(regarding the term indo-european)? | Languages show the connection. Indogerman languages are spoken in Europe and the western of asia, the anchestors of German, English and many other languages. You see the relationship in word like "mother" or "Mutter" (German), "knee" and "Knie". They didn't imitate each other, they are both "a dialect" of Indogerman. (Beside them - with no relationship - there are Finno urgic "Families" with Hungary and Finnish.) | 6d876dc9-dcf1-40c9-91bd-af2d412a16d0 |
cithtx | Why is the inflation target a range of 2-3%? What is bad about it dropping below this range? | The economy is all about people spending money and money changing hands, which is affected by inflation.
Imagine you have £100 or $100 in your hand.
With that £100 you want to buy a load of things. Due to steady inflation, that same amount of money is less powerful the longer you hold on to it.
If you know the things will slightly increase in cost over time, then it means you have a reason to spend the money now, benefitting businesses, rather than later. Money changes hands and the economy keeps working.
If you know the things will get cheaper over time (deflation, negative inflation) then you may wish to hold on to your money and wait until you can buy more things with that money. If everyone did this, money would stop changing hands and the economy would break, putting lots of people out of business and out of jobs. | e871d2f0-4401-4944-99df-d8e33a219725 |
citpld | Why does using different codecs for an mp4 file often make it incompatible for some software to use (Premiere). | Container vs Codec:
Every video consists essentially of still images played at a frame rate. Each image consists of pixels. Each pixel consists of 3 colors. Each color takes up a byte at least.
This is a lot of data. File sizes for videos would normally be massive if not for a little trick we knew, compression.
Compression takes a file and just applies various tricks to shrink its size. For instance if it sees that two frames are the same, rather than storing both, it will store one and have the place where the other one is say "this is a duplicate of frame x." But in practice things get more complicated than that, we have developed a **lot** of math tricks to bring file sizes down.
These compression algorithms are known as codecs. Software that would play video that uses them has to have the decoding algorithm for that codec to figure out what the pixel colors and what not are.
This differs from a container, which holds the video compressed by the codec, along with a lot of other things, like audio, subtitles, ect. MP4 denotes container, not codec. Its just a way of organization. | 7e733af2-0d91-4264-bc01-e3bf8db80fc1 |
citug7 | how do we measure a distance with lasers? | Light travels at a known speed, by reflecting the laser back , it can time it and give you a read out on distance based on the time it took to come back to the source. | 805efcd1-239b-4084-83eb-94ff53de3a17 |
ciu5or | Why is it that it feels so great to stretch your legs after sitting down for a long time? | It probably has something to do with aour blood pressure, and that when we stretch, ouor muscles contract increasing that pressure, making as more "alive", and "rested", which helps us be active.
Not sure, tho. | 0dd6bad9-d530-4583-943c-3c7cffa9b8e2 |
ciu8vw | if female orgasms are better than men’s, then why are men typically the ones who bother females about having sex and not the other way around? | "Better" is subjective.
Has anybody ever been biologically male, and then biologically female, and compared the two? I don't think so. So we can't ever actually compare them. | 17c9e4c8-204f-4075-9a8f-a3b6de95748c |
ciu8wf | why do international visitors to eu countries get to shop tax free? | When an EU visitor buys stuff, he pays the store for the item as well for the sales tax. The store will transfer the sales tax to the state.
When an non-EU visitor buys stuff, the initial cashflow is the same. The non-EU visitor can claim the sales tax back when leaving the EU with the item. Usually the store will pay them back at a later point, and then not have to pay the sales tax to the state.
Profit for the store will be the same. For stores located near EU borders, it is a minor act in paperwork, but a huge incentive for non-EU customers to come and buy there. Basically free advertisement.
Source: did this multiple times when living in non-EU. | 1addb5b0-a53b-425e-9b34-178a50ec1f32 |
ciufl3 | Why does hymen exist in women? Does it have any real purpose? | The vagina is formed from two different bits of the back end of the embryo, the hymen is considered to be the boundary between the two where it has failed to break down | 944def67-0ad3-42de-ac42-54034d594a71 |
ciuh16 | how do ICBM travel such long distance in short amount of time? Can they be intercepted? | It's a warhead strapped on a rocket. Rockets go fast.
If you can identify and properly track the rocket, sure. You'll need a rocket that can go faster than your enemy's. | 8ea5a44e-f50b-4773-9aaf-7e20bf384295 |
ciut3v | How are national surveys such as Pew research so accurate, especially since they interview only a few thousand people? | Statistics is a branch of mathematics that addresses questions like this. Put simply, if you choose a representative sample from a much larger population, the opinions on the sample group align tightly with the opinions of the entire population. It comes down to two things. The first is that none of us is special or unique - there are literally millions and millions of people who think about any given issue the way you do. So if you are part of a sample group, you speak for a big piece of the entire population. Second, the polling company needs to make sure the sample group isn't homogeneous - in other words, there needs to be differences in the sample that reflect the population you want to draw conclusions about. If the larger population is 55% women, then your sample should be 55% women. If the population is 20% between 18 and 29 years old, your sample should be 20% be between 18 and 29. Etc. Good polling firms interested in reliable and meaningful results know how to craft a representative sample.
/edited to correct typo | 98d9c9b6-50f2-44ae-bd3c-91d01b703f39 |
ciuwpm | Why are five cent coins often larger than ten cent coins? | For US specifically, nickles contain once contined a decent amount of nickle. Whereas older dimes had silver content. The sizing of the coin may very well be related to the volume and type of precious metal that used to be in the US coinage. | 57428807-3fe3-4186-b875-56f996356000 |
civ9vj | What is Neural Darwinism? | Basically its the idea that Darwinism (natural selection and self pruning of undesirable traits through low suvivability) applies to brain neurons.
Key part of it is that when you are born, your brain develops in a ton of diverse ways, just because. As you age, the brain goes "This part's not needed" and prunes that part off, so that things that are needed develop more.
This is important because it differs from the view that we are born with a blank slate, and as we do things growing up, our brains build things in response to those ideas. Similar end result, different process. | f6b91821-d7cd-45ef-88f0-ffde26e1a8c3 |
civfq6 | why does a stuffy nose sometimes switch sides? | You nose contains the same spongy tissue as a penis! It's true! [Here's an article about why the nose does what you're asking about. ](_URL_0_ | a8001471-4624-4cdc-9641-501e754aeaf7 |
civrws | Why does your skin radiate heat when you get a sunburn even after you've been out of the sun? | All burns do this. Lots of blood flow to the area causes more obvious heat radiation than from other areas. | 3ffebc5d-0295-4cd4-9935-9152f385710f |
ciw36r | if blood circulation is restricted in one of your limbs while you’re asleep, does your brain “wake you up” to correct the problem before it becomes a bigger issue? | You can shift position while still asleep subconsciously, or wake up. The only times I've heard of damage is when sleeping in a position that seriously cuts off blood flow while sleeping significantly drunk. | bf0916a8-12a7-4e4f-813d-38edc733aa7c |
ciwoas | How do you decide the design and shape of a product especially if it's new? And who decides it? | Most products go through a lot of design steps before they are put into public
It usually start with concept artwork, schematics & CAD design then once that is refined a prototype is made
Prototypes can be expensive to manufacture so you usually want to limit the quantity & once you have the prototype you can beta test it & tweak the design, aesthetics & materials for better functionality, appearance, ease & cost of manufacturing etc
Then you would put it out to tender with manufacturers capable of mass production & get costs - they will usually provide a sample for an agreed cost & then you choose the mass producer you want to manufacture the product
If you going to manufacture it yourself you need to factor in the cost of the setup & operation of that into your product & or amortize it over a number of products
Essentially who decides what design & materials the product have is up to the individual or company who will be selling it & usually based on consumer feedback during beta testing & focus groups | 97ec5c57-af12-4d9d-9cf9-4edc99fb5d30 |
cixdgy | How does the shoulder rotator cuff work? How is the arm able to move in a complete circle and why is the shoulder so prone to injury? | Rotator cuff muscles are a group of 4 muscles that stabilize the shoulder. They all attach to the humerus (arm bone) and the scapula ( two flat things on your back) at varous places. The shoulder joint is a highly mobile joint, its literally a ball in a socket so it can rotate 360 degrees. With this type of range comes instability, which is why you have muscles dedicated to stabilizing it. Biggest issue with the shoulder is that the ball comes out of its socket, a dislocated shoulder. The muscles in the shoulder work together to keep this from hapening. | 24439cde-0139-4d13-a503-a362317ab689 |
ciy30l | Why do some dead batteries work again after you stop using them for a while? | I'm not really sure, because this is very situation-specific (for instance, iPhone batteries have some special features).
However, many batteries will also be very hot when they run out of life. When cooled, the charges flow better, so you might be able to squeeze just a little more life out of them.
Some batteries (esp. computers and phones) turn off before they're fully empty to stop you from physically damaging the hardware. Sometimes you can trick them into turning back on after that.
Energizer batteries and such will randomly start and stop working near the end of their lifespan as the chemicals stop reacting. There's no correlation between what you do and how well they work; you're just drawing a conclusion because your brain dislikes randomness.
src: astrophysicist, this is basically a summary of what I know, but may not be 100% | 7ee37aaf-6344-4d2c-be9d-f1b82d530d74 |
ciy7p9 | How was Space X able to build better rockets than NASA having less budget and experience? | I think the other people have missed the critical element here.
The critical element was the shift from disposable to reusable rockets. Now, to their great credit, NASA did make that move in the 70s with the space shuttle, but it was a bit too early, and the whole shuttle project was a bit of a logistical and political shitshow.
By the time SpaceX came along, technology had advanced considerably. Here's a great talk by Raffaello D’Andrea explaining it [_URL_0_](_URL_0_)
In short, between the Space Shuttle and the Falcon 9, feedback control got good enough, and cheap enough, that the idea of landing an otherwise traditional rocket vertically was very feasible. By this point, the Shuttle was seen as a failure - technologically impressive, but economically unviable, and increasingly outdated. So NASAs focus was off of reusability and onto cheap disposability. In that environment, dumping money into R & D is a bit pointless if you have designs from the 60s that are reliable and well understood. They'll only fly once, and the cost of space flight is really in the minimization of failures. So, advances in engines and control systems largely stopped.
SpaceX saw things differently. Believing they could take what looked like a conventional rocket and land and refly it, meant they could change the economic model. Launches were rare because the cost of disposing a rocket each time was high, and because the cadence was low - there was no incentive to build out production lines that could spit out a rocket every two weeks. But if you could reuse the rocket, even just one more time, you'd need half as many of them. Refly it 4 times, and you need to build only 20% as many. So, SpaceX went for a commodity strategy - build one really really good motor to serve first and second stage, rely on modern control electronics to regulate 9 motors operating together in the first stage, and engineer for reusability, and get your reliability that way, and dramatically cut costs to fly the rocket and use that money to pay for the new R & D. Digital feedback control wasn't the only thing that had dramatically advanced since the 70s, so had manufacturing techniques and materials engineering. So SpaceX could build simpler rockets that performed better than was possible in the 70s.
NASA didn't want these rockets, believing in their tried and true approach, but private companies did want them and with time SpaceX won them over. Bezos saw the same opportunities, as did others. Existing companies didn't see the opportunity because their value was in their tried and true methods, their decades of engineering experience at this, their detailed knowledge of how these old system worked, which made them reliable.
This is also a story of why established companies rarely pivot their business model to adapt to changes, and why startups and other new entrants are key to advancing industries. They can take these risks, they can invest in the new technology and not invest in the legacy technology. Had SpaceX failed, we wouldn't even be talking about them - so there's some survivors bias baked in here too. | fcb6fc81-924d-45a6-b814-ee179cfc1754 |
ciyfiq | Why do Night Terrors Occur? | Night terrors happen when the waking-up process gets out of sequence.
During REM sleep, the dreaming stage, our brains shut down signals to our muscles, effectively paralyzing us. This helps prevent sleepwalking.
A night terror occurs when you regain consciousness before your brain has restored muscle control. You start becoming aware of the real world before the dreaming has fully terminated. You can see your bedroom walls, but you can't move to sit up. Your still-kinda-dreaming brain panics and instantly starts fantasizing explanations of why you can't move, and may create visions that seem very realistic for a moment until that dream state finally switches off. | a930e09a-afae-4f8e-a610-e5ffe3478159 |
ciyjhf | How is it that so many people die with such big debts, and their creditors are still net positive on the amount lent? | People usually pay significantly more due to interest than a loan is originally worth. This allows the relatively minor loss of money to be offset by the deceased's prior interest, as well as the interest of other debtors. It's not like the majority of the population dies with 100k debts on their shoulders. Also, when people die in debt, this debt is often paid for in part by selling everything they owned. | e18d52ca-2ca0-42a6-91fc-febe1763776a |
ciyw69 | How do they do a print run for a magazine and know what the right sort of paper is? | Magazines are typically done on offset presses, using standard sheet sizes. The type of paper printed on is specified by the customer, generally proofed before a full production run. Matte vs. Glossy is often a varnish applied on top after printing is done, before it goes to binding. There are usually multiple machines that go into making the finished product. I work for an OEM that makes/designs/services these types of machines, it's a huge industry. | d74e60cd-2c76-442f-a4c1-9f97b89b528f |
ciz0yx | Why do cable internet providers offer such asymmetrical speeds compared to their fiber counterparts? E.G. Their upload speeds are so much slower than their download speeds. | There is almost always a bigger need for downloading information than there is for uploading it, and the cables that cable internet travels over are more limited than fiber optic. So, cable and DSL companies prioritize download speeds by using more channels for downloading than for uploading. | 997953fc-c606-4d84-b351-66ee9fb3cf4c |
ciz1if | How do smaller online flight travel agents work? | They act as a reseller for tickets via a centralised database for them. Since they can determine their own profit, higher volume (relative to them) allows them to discount. This makes filling planes a surer thing, and many people (rightfully so), still drift direct carrier to buy.
They never work with all the airlines, and I had a long haul flight that was a bit lower than the standard price but I had near 50% luggage allowance and a couple of additional minor benefits. | f5952192-ec84-45b4-9f4d-8465441fa29d |
ciz9hj | In the "Hubble scientists have released the most detailed picture of the universe to date, containing 265,000 galaxies." Picture; what is the method of expanding that map, and from what orientation are we observing from? | The map is stitched together from many different observations, so expanding it would be done by adding more observations near the edges.
"Orientation" is a bit vague a question, but the field is within the constellation Fornax, in the southern hemisphere southwest of Orion. | 59c2efb7-3636-4d9f-beed-9567f102e5d4 |
cized5 | Why does Honda sell so poorly in Europe? | In general cars are much smaller in Europe than in the US because of narrower streets and less space in general. For example what is considered a humongous SUV over here (Audi Q7, BMW X5) would't be a particularly large car in the US.
Therefore there's no market for US cars. I see Honda being named as a very small and fuel efficient car by americans a lot (at least on reddit) but compared to other European and Japanese manufacturers its really not that great.
For example you can get super efficient french diesel cars for a great price (Citroen, Renault) or if you like the "prestige" you can go for a german car. When it comes to japanese vehicles you see quite some Toyotas and more recently also korean cars like Hyundai and Kia which have ridiculously long warranty periods and really affordable hybrid drive trains.
If you see all that Honda is just one manufacturer among others and (in my opinion) their deisgn is quite weird as well. They look straight out of transformers movie nowadays which is weird.
Regarding Ford you see a lot of the smaller models like the fiesta or Ka which are made in Germany or the UK and none of the monstrous american trucks for which you woulnt't find a parking spot and at 6.5$ per gallon for basic gasoline in some countries you don't want to fuel one either. | 4faad5b1-2764-4d63-886b-9591acfb0216 |
cizl6c | How does dish soap dissolve oil and grease? | The detergent is composed of molecules with one end that is attracted to water and one end which is attracted to oils. Oils and water normally don't want to mix, but the detergent acts like an intermediary and forms tiny bubble membranes around the oils, allowing them to be washed away by the water. | f87b6709-5a70-454d-bb25-9d0688f51344 |
cizser | why do animals act casual and gaze around like nothing’s happening, even though they might be getting killed or are the situation is serious? | Animals usually dont have similar facial expressions to humans, the exeption being our closest genetic realetives like chimps and such. Even then the facial expressions mean very different things to them. And animal with it head and ears up scanning its surrounding is looking for a potential threat so it can run the opposite way usually. | 865764ce-754e-4330-aa7c-ff897c40162a |
cj026h | How did Eratosthenes figure out Earth is round and calculated earth circumference 2000 years ago? | Grab a paper towel tube and hold it up to your eye like it's a spyglass and you're a pirate. Declare "yarrr!!"
Now use your new cardboard spyglass to look close to a light, but not quite. The line from your eye to the light is blocked by the wall of the tube, so the light doesn't reach your eye. If you turn your head just a little bit then the tube aligns and you can see the light. Now you know that the tube is aligned between your eye and the light.
Eratosthenes did much the same, but with wells. These wells are long tubes that were bored straight down, where "straight down" is a direction that changes as you move from place to place.
Most of the time sunlight won't directly shine on the bottom of a well, since the sun isn't directly overhead. However, at 12:00 noon on certain days of the year the well and the sun align. Someone leaning over the edge of the well will see the shadow of their head against the water at the bottom of the well.
On that same day at the same time someone some distance away could try the same thing, but they find that the sun isn't aligned. It's a little bit to the north or south, depending on whether the second location is north or south of the place where the aligned well is. (Aside: if the second location is East or West then that also messes things up, but we'll assume here that either the second location was due north or due south or that the second observer makes their observation at their own local noon).
At that location the observer can erect a tall, vertical pole of known height and look where the shadow of the top of that pole lands. Based on the length of the shadow and the length of the pole they know the angle of the sun.
The final piece of the puzzle is the distance between the two locations. This allows the observer to set up a ratio: "If I walk XXX miles (or stadia, as the case may be) then the sun changes angle by YYY degrees. Therefore, to make the sun change in angle by a full 360 degrees I'd have to walk < circumference of Earth > miles." | e9ca5e7c-0497-4f33-85f7-17bf38411718 |
cj02qi | How does a little bit of powdered gelatin (proportionately) solidify a large amount of liquid? How does it work? What's the reaction or physical process? | The small amount of powdered gelatin disperses into a kind of large, cross-linked web structure throughout the liquid, holding it together. Since the fibers of gelatin are very thin and widely spread, the block of jello is pretty fragile and jiggly and not very physically strong. | acba542c-8f99-4121-8b1c-df494f39bda6 |
cj03o6 | Why is the power of car engines measured by horsepowers? | When James Watt was touring the country selling his steam engine, it was easier to tell people how many horses they could replace than how many joules of work his engine could accomplish per minute... or how many pounds of force it could apply a given distance in a given time. So he came up with a unit of measurement that people could relate to - horsepower. So a 1 horsepower steam engine would be able to supply the power that a single horse could continuously exert. | 2efc1362-1d51-40f9-9d16-548a5a59fa93 |
cj0d4u | How does specialized bacteria find its target? | Bacteria does not "find" a target. Instead, you have so much bacteria just going everywhere that some inevitably finds some food it can live on. The bacteria that does not find food reproduces and makes more bacteria which goes out hoping to land on even more food. | 2e982cb7-a279-4e6e-8c56-498a01cfe28e |
cj0jx3 | How does recycling get “contaminated” ? | The issue with contamination is that you cannot separate or sort it. Recyclable material get contaminated if they get into contact with un-recyclable materials that you cannot easily separate. For example, although a cardboard box is recyclable, a pizza box isn't recyclable because the grease from the pizza cannot be separated from the cardboard, hence the pizza box is "contaminated". It's way too expensive to try to remove the grease from the cardboard, so the entire cardboard is thrown into a landfill. Also, the grease from the box can leak from the box and contaminate other objects in the lot, meaning that the entire lot must be discarded.
If you left a receipt into a plastic bag, it's a different story. The receipt could get manually removed quite easily from the bag, and the bag could proceed to be recycled correctly. | e77de4bb-b98a-45a0-ba03-61df4778dd79 |
cj0otb | Why can some brands completely rip off other brands designs on certain products? | Per a quick google search, they are often lawsuits for this. However, I’d hazard a guess that court costs and lawyer fees are factored in before moving forward. Generic copy at Walmart maybe only profits 40k$, but the lawsuit would cost 200k for both sides. It’s now a loss to sue and not worth moving forward. Adidas sued Walmart for infringing on their 3 stripe design a while back and won. Those shoes now have 4 stripes.
Edit:changed a letter | 9c9f4839-55c3-446d-9743-33d3384a33cd |
cj0ppo | Why does animal camouflage, for the most part, not work on humans? We can often see what the camouflage is attempting to do, but we can usually spot an animal pretty quickly. | Oh I actually think I might know this one!
Humans are really good at recognizing patterns. We see faces in everything- toast, clouds, stone, etc. We just automatically look for patterns in things, so when we see a spot in some leaves that seems to have a separate pattern, or doesn’t quite line up, we’re likely to notice it. At least, I think that’s the reason! | 80f36b7a-afe8-452e-b9a0-a6c6b778e1b6 |
cj131z | What’s the importance of restarting your computer after updating an application/program on a computer? | Computers run on sets of instructions telling it how to run all the parts of the computer and build an interface so you can use those parts.
Say you're following a recipe for a cake. Then you finish the cake and someone comes along with a better way to make a cake by adding another ingredient and changing how much salt is used. You can't unbake your cake at this point to try it out. You have to start over from scratch and remake the cake.
So when an update happens, you have to restart the program or even the whole computer to before you were using those instructions that changed. So the computer can follow the newer, better instructions when it builds you your interface. | b50a48b2-bd0a-4d7e-b105-9c684adef4ec |
cj1c8e | How is it that leaders like Putin always find a means to poison their opponents, yet no opponent groups are able to do the same to him? Not a single rogue member of his team attempts it? | So Russian oligarchs are fucking scary. One of the best stories to come out of the death of Stalin was about the guards on duty outside his bedroom. Reportedly, they heard him hit the ground when he died, but refused to enter the room for the next 8 hours because he might be angry at being disturbed and kill them. | f3158de6-36e2-4ccf-b263-8eb1f8791a76 |
cj1pec | When looking at the moon, you can see a hint of blue on one side of its edge, and red on the other. Why is this? | It is called chromatic aberration and it is from the lens of the camera used to take the picture. You now how a prism used to split light will bend light different angles depending on its wavelength? The lens does that too, just the effect is attempted to be minimized. | 6cea51f5-6e56-48c2-a7d6-5f4930cdb905 |
cj20jj | Why does some kinds of skin get darker when they go out in the sun instead of getting sunburnt? | It depends on the amount of melanin you have in your body. Darker skinned people tend to have more melanin and are therefore more resistant to sunburn. Usually you can determine the amount of melanin you have in your body by you skin, eye and hair colour. For example, a red headed person with blue eyes and freckles probably has very little melanin, while a person with brown eyes and an olive complexion would have more.
Either way, wear suncream. The sun is dangerous regardless. | 122276de-fbac-44cf-b0d1-65ebd3bcd6f2 |
cj20mp | why is a chip on a credit card considered ‘safer’ than swiping the magnetic strip? | Magnetic strips can be much more easily duplicated than the chips.
The strip can be duplicated just by reading the swipe, since the data it gives *is* the data it has.
The chip, instead, gives an encrypted code based on what you ask it by combining the value you gave it with a secret one it has, and even if you ask it hundreds of times, you won't be able to figure out the secret number it stores inside it. When the reader says to it "what value do you get when I give you Value Y?" the chip responds with what it gets, and then that is checked by the institution that issued the card (who know the secret number too so can do the same calculation and see if the results match). | 3a2697a2-b7a1-4a9d-a9e5-e1e1a0bc5701 |
cj2enw | I always wondered why the "One a day" vitamins have to be so uncomfortably large. Why not make them into two regular sized pills and call it "Once a day" vitamins? | some pills do that. See: the gummy one a days.
but generally, it's easier for people to understand to take one pill once a day than two once a day, even if it's little uncomfortable. | 3f8184c5-ba8b-4774-b981-2ad5ec93e080 |
cj2kf7 | Why is the QWERTY keyboard's arrangements the way it is? | Typewriters are complex mechanical contraptions, so having commonly used keys next to each other makes them jam easily if you're using an alphabetically ordered keyboard.
QWERTY has the keys more or less evenly spread so that typewriters could write at high speeds without jamming, and once the convention set it became nearly impossible to sell alternatives.
Dvorak is one relatively popular (and supposedly faster) layout, but since learning different layouts takes a lot of effort, QWERTY is the norm. | a2d677c0-b128-48de-b611-24377f7ce5df |
cj2vga | What would happen if the UK leaves the EU with a no-deal? | Once we left we would immediately then have to do a trade deal with Europe as its such a big and important trade block.
The term no deal is not accurate. We would still need to do a deal but we'd be in an even weaker position. | 3c76842b-f461-49b2-908a-dd5ca30fd55e |
cj3j5q | How did we initially measure the distance to other planets precisely enough to send probes to them? | We track their movement through the sky. There is actually a lot of interesting history behind this.
The effects of gravity and the math of orbits were always well understood. Kepler and Newton figured out how gravity and orbits worked (which is interesting since Kepler somehow figured out his three laws decades before Newton figured out how gravity worked, nonetheless it was quickly found that Newton's law of gravity produced Kepler's laws as a consequence).
For instance Kepler's third law states that "The square of the period (time of a year) of any planet is proportional to the cube of the semimajor axis (distance from the sun) of its orbit."
The interesting thing about this was this led to the existence of the astronomical unit. We knew that the period of Earth's orbit is 365 days, we could observe the orbits of other planets to see how long they orbit, this means we could calculate how far a planet was from the sun based on how far the sun was from the Earth.
But finding out the distance from the Earth to the sun was a vastly trickier undertaking, which is why many early measurements are expressed in astronomical units, the distance from the Earth to the sun which we just didn't know at the time. The best way we knew of measuring it was using parallax but that itself was pretty difficult due to the sheer scales of the distances we used, and often the best measurements would only happen by observing transits of Venus from different points on Earth which is why there was a bit of a scramble during this time to send out explorers all over the world to observe this. The basic logic was that we worked backwards from here, using parallax geometry we could calculate the distance to Venus, thus knowing the distance from Venus to earth in terms of AU, we could figure out the distance from the sun to earth.
We got pretty good estimates from these, with accuracy to a few percent. We continued to refine our estimates by taking more measurements but the big breaks only happened in the 20th century, when we used radar technology to send a lot of microwaves to near earth objects like venus where the microwaves would bounce off and hopefully be detectable by antennas here on the ground after a while, using this time and the speed of light we could calculate distance to these things. | 458a7408-cab4-4e0f-8755-ffb2f20ab32e |
cj3lbq | Why does coffee/caffeine help migraines? | Caffeine is a vasoconstrictor, so if the migraine has a vascular component, caffeine may have an effect on blood flow. | a9db4a4c-616b-47c2-93a0-47587ca1aaca |
cj3rpj | How do some cars have a birds eye view of of the car when they’re parking? | The car has cameras in the front, rear, and in the two side mirrors. Those images are stitched together (kind of the same way that your phone creates a panorama) to give a kind of 360° view of the car's surroundings. That image is then displayed in such a way that it looks sort of like a bird's-eye view instead of like the 360° panorama that it actually is. | 28f07d3a-4950-4c6b-89d8-cac7ddb4aeaa |
cj3vk3 | Why does alcohol make you feel warmer but actually makes your body temperature colder? | Alcohol dilates your capillaries (the smallest blood vessels closest to the outside), increasing the flow of blood through them. More warm blood flowing through capillaries makes you feel warmer, but that blood is being cooled down from being exposed to the cold, and that brings down your body temperature. | 7b437b68-7663-44f7-9aa1-24abc3227a18 |
cj3z64 | How do wetsuits work? | Step 1: Submerge wetsuited body in water.
Step 2: Wetsuit fills with water.
Step 3: Body heats up water now trapped in wetsuit.
Step 4: Body stays warmer than the water outside of the wetsuit.
Addednum: Wetsuits typically range from 3mm to 7mm thick. Thicker wetsuits provide more protection against the cold of surrounding water. | acdf5632-8df3-4f72-a598-1803d0c9f994 |
cj3zai | What would be the significance of a non-carbon based life form? | It would be tantamount to what Thomas Kuhn termed a ‘paradigm shift.’ Basically, it would revolutionize the most basic conclusions scientists have had about the origins of life for hundreds of years. | c34d6705-ff40-4a1b-9533-2b261078df00 |
cj46by | how are (mostly) whole crashed planes transported to be dismantled or repaired? | Most large aircraft are actually modular. Wings, tail, etc only require a few bolts and some cable disconnects to unship them. Then, they can be loaded onto trucks ( or trains, I’ve seen that once) for long haul shipping. | 89aabe8f-df34-410d-8bf9-a38dd64bcee7 |
cj48qa | why does looking at the sun help you sneeze? | Its a condition that only affects some people (me included) its to do with the nerve endings in your face getting crosswired. The eyes and the nose are very close to each other so some people have this problem. | 9277d51f-5c6a-498b-85e0-8822d3a3534b |
cj4a8h | "What happens to the cavity in a building where the crane was initially." | You are all lunatics. Cranes don't build the structure around themselves, the crane will be either free standing next to the building or sitting on the current top floor. When they build a new floor they move it up another level.
So your question has no answer because it isn't a problem that exists. | 5ad4d2fc-0250-4e80-a209-acd93d473911 |
cj4hgf | what’s the difference between certificates, diplomas, and degrees? | Certificates are typically awarded for a short term study in a specific field. Diplomas are awarded for completing (typically) a multiyear study at a non university level. Degrees are awarded by universities for the completion of a multiyear course of study. The first level of degree is a Bachelor's. Graduate degrees are Masters or Doctorate level. | 5fa3ca51-0a3b-49d3-bdfe-ce4cdc692565 |
cj4p93 | How does the Game Genie work? | The Game Genie and Game Shark peripherals were special cartridges that sat between the system and the game cartridge. This lets it read and modify memory in any way it wants.
The special codes you put into it contain the memory address and the action to perform. It can be as simple as "Set this value to X and don't let it change" or something more complex like "When the 'A' button is pressed, add 4 to this value". | 1b13df23-8cdc-4b2d-a129-3bdab7ba3ed1 |
cj4qld | how did people in places like florida get ice before machines were made to make ice. | Ice was harvested in cold climates such as New England during the winter time and stored in cold places such as caves, while being packed in insulation, such as saw dust. Ice could be stored year round in some locations.
Ice was then transported to warmer locations, such as Florida in ships, again using sawdust as insulation. Transit losses (ice melting) was very high. | 282e725c-8a19-4024-9259-494c806f94bf |
cj4tjk | Why do strobe lights cause seizures for certain people? | The bright, flashing lights irritate the nerves of some people to the point of overexcitement, causing those nerves to send continuous signals to the brain. The brain can’t process it adequately, so it, in essence, shuts down and reboots. | 84103ac0-ba20-4a78-9cdb-8a5e462cb074 |
cj5358 | Rainbow like waves on cellphone screens while using sunglasses | ah so this is probably more suited to r/askscience, but I'll take my best guess as a former optical physicist.
Your sunglasses have polarized lenses, which means only light that waves a certain way can get through them. But your screen also refreshes a certain way, so at certain angles, this refreshing could be visible through your sunglasses because the light will wave along those refresh lines. The lines are colored because there's three or four LEDs in every pixel so the screen displays (most) colors, but they might, again, refresh at different rates.
and that's my best guess. | 05aa1bef-037d-4079-a9d0-868a24421205 |
cj540r | How do babies in the womb not get the negative affects of blood rushing to their head while being upside down for so long? | Imagine being upside down in a pool. Not quite the same blood rush to the head, is it? A fetus is basically in a fluid filled sac. | d5cecee8-4d9b-4c4c-9651-9dd30b32adec |
cj58xq | glass slag and how it’s formed | i'm assuming you're talking about slag glass because that's what google turned up (let me know if this isn't the case). Slag is a general term for impurities that come out of metal when it melts. Originally, slag glass was a glassy impurity (aka slag) that comes from smelting iron from raw ore. when you melt metals, various impurities separate out from the metal and are siphoned off. Later, slag glass stopped being made from ore run off and was made using multiple colors of glass to get the same effect. | b9bf07a0-621f-4f85-89f1-bb3183eb7642 |
cj597n | How does electricity work? | If you put all your Hot Wheels in a row on the coffee table or counter so they got from edge to edge, and then get just one more and push it in line so that it ends on the countertop/table, it'll push the one on the other end off.
That's how electricity moves. Metal is made of atoms, and atoms have electrons. The outside electrons in the atoms (called "valence") are the hot wheels lined up on your table. The outlet siupplies one more electron into the chain of atoms in the power cord, and out the other end falls an electron to be used by whatever work needs to be done. | 654396d8-612c-4053-9881-1aacf839e7bd |
cj59a1 | Why can some plants live in water, but the same plant will die if it gets too much water? | Plants use water to transport nutrients to the plant cells.
They evolved to do that optimally in the environment they exist.
When subjected to other conditions it impairs their ability to function properly. | 9f925def-02fa-4227-9f13-a441f52c13b6 |
cj5r2y | How does the moon control the ocean waves? | The moon does nothing to the waves themselves. Those are created by the wind. But it does change overall water levels through tides.
Gravity is stronger the closer you are to the source. Let's break this problem into three parts to simplify it.
The surface of the Earth directly under the moon is closer that the middle. And this region is closer than the side opposite the moon.
So closest side feels strongest gravity, middle a middle amount, and the far side the weakest.
Water is about to move, so it's going to pool up where it's tugged the most, underneath the moon.
The Earth gets tugged towards the moon too, which "leaves behind" water on the far side, which seems to sell and rise away from the surface.
So we get two bulges, one on the bear side, one in the far side. The Earth is also spinning, which changes what land masses are on the high and low zones as the day goes on.
The sun also creates tides, but smaller ones. When the sun and Moon line up we get stronger than usual "spring" tides, and when they are a at right angles we get weaker than normal "neap" tides. These happen monthly as the moon permits the Earth. | 8028c81c-5ceb-408b-9535-e8e3b259f773 |
cj661k | Can you sweat underwater? Why? | Sweating is your body’s way of cooling itself off. You body secrets swear which evaporates and Takes gets along in the process which cools you. You wouldn’t have any need of sweating underwater (or while wet) as the water itself would do the same job.
But you still sweat if you get hot enough. It’s an automatic process the body performs so if your body gets to the sweating threshold, you will sweat regardless of being in water or out. You just won’t notice it if you are in the water. | bc5df8a1-372f-4395-86e8-d7efa18d74fe |
cj68wy | Is space infinite? | There really isn’t a good answer to this without some speculation being involved. The universe as we know it is constantly expanding from what we believe is an event known as the “Big Bang”, which unleashed an incredible amount of energy and mass. To observe what’s beyond the universe you would need to move very fast for much longer than the average human lifespan.
Modern science estimates the speed of expansion or Hubble constant to be about 71.9 kilometers (44.7 miles) per second per megaparsec (one megaparsec equals about 3.3 million light-years). Assuming you could move faster than the expansion, and you lived long enough to reach the “edge”, you might find another universe or absolute nothingness. For all we know you’d find a tentacle monster that would fall in love with the human species if you’re a fan of Futurama. | 78daff67-9a94-4cdf-bf75-5a97e3fe3a5a |
cj6cs2 | How was triceratops mouth/beak optimized for eating enough jungle plants/grass to sustain its body weight? | A combination of being exothermic (what they used to call cold-blooded) and just constantly eating.
There's not much specialized about their mouths/teeth except thst they can cut the plants and start digesting them quickly. | d68b486c-1854-48ec-907e-157cd74aa963 |
cj6js4 | Vis a vis abortion, why is it so hard for doctors and biologists to pin down "where life begins?" | This is an area where science/technology, religion and philosophy all have something to say. Therefore interpretations and definitions are contextual.
In certain respects, advances in scientific knowledge has made the issue even less clear. Science doesn't advance in a consistent way in all areas. In today's situation, there are more methods to keep a body functioning even with severe damage to many organs. However, science hasn't made much progress in defining consciousness or sentience in other than mostly abstract terms.
A philosophy professor once gave this scenario (probably common). Say you went to bed one day and woke up to find that someone had connected you (medically) to another person (an adult, say). Someone leaves you a message that this person is sick and will almost certainly immediately die if they are disconnected from you within the next 7-8 months but if left connected, they have a good chance of surviving. You, on the other hand, are compromised and also stand a low (but not zero) chance of death due to this connection. Are you obligated ethically to maintain this connection? Would you support a law saying that anyone in this position is criminally responsible if they decided to disconnect? | f782b1ff-6448-4932-9cd3-f0b46f84bb4e |
cj6vgd | Why is moving air (eg. wind) colder than stationary air? | Not an expert but from my understanding...
You is hot.
You warm the air near you.
Air near you now warm.
New Air moves into that airs place.
New air was not previously exposed to your hotness so is cooler in comparison to old air. | a6a8876f-b210-49d9-9a4b-471f016d8126 |
cj71v8 | Why did Korea split into two countries during the Korean War, but not the U.S during the Civil War? | Because during civil war the side that was against splitting won. During the Korean war neither side won and the war technically never ended. There have been many skirmishes at the DMZ since the Korean 1953, notably [in 1976](_URL_0_) where American soldiers were chopping down a tree in the DMZ and the North Koreans Army killed 2 Army officers with axes. | 6e6488c8-400c-48e1-8050-5f0c556a66c2 |
cj7ifk | Why hasn't the US gone Chip and Pin even though the infrastructure is in place? | In the US you aren't responsible for credit card fraud regardless of why that fraud occurs. This is not the same in the EU. EU laws on cardholder liability vary from country to country, but in most countries you are liable for ~150 euros per transaction, unless you acted "carelessly" in which case your liability is unlimited.
This is why chip and pin is widespread in the EU: it provides an easy mechanism for banks and credit card companies to shift the liability of fraud onto you because if the fraudster has your pin then you are deemed to have acted carelessly - and there are many cases in which a fraudster could get your pin despite you not acting carelessly, meaning that you get stuck with the fraudulent bill through no fault of your own.
The pin itself adds almost no security - it only protects you in the extremely rare case where the card is stolen and you don't report it until a purchase has been made using a chip reader.
In the US, the pin doesn't change the liability status of a fraud case - the card issuer is 100% liable regardless of how "careless" the cardholder was.
There are, however, costs in switching over to a pin system. The first of those are on the part of card issuers who have to get all of their existing customers to switch over to using a pin. Although it may not seem like it, convincing people to switch over to something like that is horrendously expensive in terms of the educational materials you have to send out and additional customer service calls you have to take from people who are confused about the new system.
The second cost is paid for by those merchants who are used to taking a customer's card and charging them at a single, stationary point of sale station - ie restaurants - who now need to purchase an entirely new point of sale system. This is, again, horrifically expensive and not something that merchants are inclined to do - getting them to even roll out chip readers in the first place was a multiyear process and there are many that haven't switched over.
So in the US you have a situation in which chip and sign is the established norm and switching to chip and pin offers no meaningful benefit to anyone but is expensive. | e583ec65-1942-4057-b6f4-fd23c7f7b379 |
cj7p1z | How do colds happen? | The common cold is simply a virus, specifically one of over 200 different strains of viruses. They spread through the air or by direct contact. Most symptoms are simply the body's immune response to the cold. Despite the name, there's little evidence that it's actually caused by cold weather. | 716e6fc6-0f24-4322-bf55-801f035c6a8b |
cj7xoj | why do mushrooms naturally grow in a circle shape? | Many types of fungi feed of plant matter buried in the ground. They form a vast network of roots, the so called [mycelium](_URL_0_). This network grows underground, absorbing all the nutrients, at at some point they use the stored up nutrients to grow above ground to spread their spores with the wind. So if you see a bunch of mushrooms clustered together, those things are all just like tips of a giant iceberg growing beneath the ground. This network will grow outward as long as there are more nutrients to be found.
The reason that they form these circles is that the mycelium dies off once there are no more nutrients in the soil. So while it grows outward, it dies off in the center. If the conditions are just right, it'll form a nearly perfect circle in the process. | a0567d79-2257-470e-8e0b-09c94a9e4ddc |
cj839u | In movies and TV shows, when actors and actresses snort a substance (cocaine, heroin, etc.) what are they really snorting? | It depends on what they're doing with the substance. If it's just going to sit on a table or get cut into lines, they use a mixture of corn starch and baby powder. If it's going up a nose, they'll use powdered lactose instead (or vitamin B powder if they're lactose intolerant), and they might coat the inside of the straw with Vaseline (because the powder will stick to it instead of actually going up their nose). They'll use slightly different mixtures and add different innocuous powders to get different colors if they need different drugs. | 866c5b26-0080-4af1-b274-3c57ed2afa82 |
cj84je | How are polar bears able to go months without food? | Animals that hibernate build up fat reserves in the summer and then go into a state where they minimize how much quickly they use that up by remaining inactive, slowing their metabolism and lowering their body temperature. It's not limited to polar bears, many other bears do and also animals like hedgehogs, tortoises, lots of flying insects, bats, mice, squirrels to name a few.
Polar bears are an extreme case as food is virtually unobtainable in the winter months so they would probably use more energy than they gain by foraging. Some other animals rouse up at times when the weather warms, more like is dozing than full sleep. | 41f44921-8ee4-4d4b-a93f-661ff002ecc4 |
cj8asp | What is a geometrically safe container to prevent radioactive materials to reach criticality? I've been reading a lot about nucular accidents and there is often this phrase of a "geometrically safe" container popping up. What is it and how does the geometry of a container prevent criticality? | You get chain reactions with nuclear reactions because radioactive material decaying can cause other radioactive material nearby to decay to.
In nuclear reactors you want the reaction to be just enough to keep going and give of some heat, but not more. With bombs you want them to really get worse exponentially fast and give of as much energy as possible in a very short time.
When transporting stuff you ideally don't want it to explode or even keep heating itself.
One way to do this is to keep the mass down.
another way to do is is to distribute the mass so that it won't allow a chain reaction.
You can have the same amount of material in the form of of a solid sphere or a thin rod. a sphere is ideal because everything is close together. If an atom decays it has the best chances of getting other nearby atoms to decay to. In the shape of thin rod you have the same amount of material but much of it is much farther away an atom decaying in a rod has far fewer neighbors that it can get decay too.
The idea is to ensure that as much radiation as possible is wasted hitting something other than the rest of the radioactive material. | 4230bff7-1ff2-4b7f-8b48-3fe9e60d0351 |
cj8bqr | How do different animals age differently? What is the difference in their physiology that makes them age live longer/shorter lives than us? | Heart beat speed is a common factor, faster heart beat tends to equal shorter life expectancy while slower heart beats equal longer life expectancy. I read this once so take with a grain of salt. | 24a55598-4e3b-4fdf-8e5f-eb05ea1c6e2b |
cj8f2g | why is it better to pre-heat the oven when cooking meat? | If you need to cook for a long time, then it doesn't matter.
If you need to cook for a short, set amount of time, then it matters because each oven takes a different time to heat up, so the recipe would be inconsistent between different ovens unless you preheat them. | 87df63ca-a0af-40a2-90dd-e8d527d93f9c |
cj8i3f | Heat tends to rise above colder air, but what happens when there is no gravity? | When there is no gravity, the hot air will simply mix with the cold air until they reach the same temperature.
The long answer:
Cold air is denser, meaning that in a given volume of say 1 litre, there is more of air that can fit into 1 litre if it is cold, then if it is hot. So 1 litre of cold air weighs more that 1 litre of hot air. Since weight is the force exerted on mass by gravity, 1 litre of cold air weighs more than 1 litre of hot air, and it sinks. This reveals the misnomer 'hot air rises'... Its more like cold air will sink in hot air because it weighs more than the same volume of hot air. If there is no gravity, there is no sinking, so the cold air and hot air will simply mix and reach thermal equilibrium. | d0c6b526-ce83-46e6-8dc2-ea5ceeab0f9c |
cj8nii | why do moths wait until the sun is down to be active, yet seem to spend all their waking hours around lamps? | they normally use the moon to navigate and these lights just confuse them. It's not like they "like" or need the light to live. | 813cf9db-0950-4639-8c3d-6e91e22be928 |
cj8ort | How can someone make a fraudulent transaction just by knowing my Debit Card Number and CVV? | i didn't need any Pin or anything to add my credit card to amazon, they might get suspicious if the name on the adress is not the same, but that's easy to change. | ab621bf2-257b-4dd3-a951-34cf38097529 |
cj8wer | How snorted substances affect the brain without properly being ingested or injected | Chemicals dissolve in the mucus which coats most of the surface in the nose/back of throat. It can diffuse through the cells and enter your bloodstream directly. Same thing when you put something under your tongue, like lsd. | 81dd08b4-11ae-4125-88c8-dc389d136268 |
cj8x7p | Why do gunshots sound so different at distance? | The bang at the gun is from the explosion of propellant.
The snap downrange is the shockwave from the bullet going faster than sound. This sound is drowned out by the bang when you're closer to the gun.
There is also a whizzing sound as the bullet destabilizes or ricochets and starts to tumble. This is caused by the rapid change in air pressure as the bullet goes from aerodynamic point first to sideways into the air and back. | bb314c88-3e2c-42da-a21f-7b4f42c3f7f5 |
cj9pu2 | How can our brains distinguish between men with high voices and women with low voices? (Eg. Charlie Day vs. Emma Stone) | Even if the pitch between a higher pitched male voice and a lower pitched female voice is the same, a male voice sounds different due to differences in the vocal tract and the resulting acoustic resonance. This is called a formant.
However, it’s more difficult distinguishing between the two when this quality of the voice is being masked by distortion, such as when hearing the person’s voice through a walkie talkie. | ba66a7fb-3225-4894-ae04-05d98cc75361 |
cj9qtg | what is the science behind a seizure, including how it ends? | There are lots of things that can trigger seizures (genetics, electrolytes, infections, etc.), but the key thing to keep in mind (no pun intended) is that neurons work through the flow of electrolytes which creates an electric charge. This charge can be communicated from one neuron to the next through neurotransmitters.
Let's say that something causes irritation to the brain (it doesn't matter what, but let's assume someone has a brain bleed). That area becomes really inflamed, and this causes the neurons around it to become overstimulated. It also makes neurotransmitters that are normally confined to a synapse leek out into the rest of the brain. Now, you have neurons that are way too stimulated and extra neurotransmitters floating around which causes the rest of the neurons to start firing as well.
At the same time that this is happening, the normal processes that that brain relies on to slow or stop neurons from firing become overwhelmed, so neurons are over firing and also unable to stop firing.
The shaking that some people have during a seizure is just a symptom of this uncontrolled brain activity. (Remember - the brain tells the rest of the body to move, so if it's firing erratically because of a seizure, it can manifest in convulsive type movements).
People who have genetic epilepsy usually have an issue where the channels that electrolytes move through in neurons are either over- or under-active, which has the same effect as above.
If they're not stopped by medications, they'll usually burn out on their own. After firing, neurons have something called a refractory period where they aren't able to fire again because they have to get their electrolytes back to normal, so over time, seizures usually slow down and stop on their own.
Hope this helps. | a602ae79-7774-47f1-8db1-af93f5e01759 |
cjacvy | How are no-confidence votes in the UK different before and after the Fixed-Term Parliments Act of 2011? | Previously:
* The PM could ask the Queen to dissolve Parliament at any time and hold new elections
* If the government lost any "important" vote (a confidence motion or supply bill), it was *expected* the PM would do that
Now:
* The PM can't ask the Queen to dissolve Parliament at any time
* The government can lose any and all votes, it doesn't mean there has to be a new election, unless...
* Parliament passes "This House has no confidence in HMG" (with a simple majority, e.g. 326-323, or even 1-0 if nobody wants to vote).... and Parliament does not pass "This House *has* confidence in HMG" within 14 days
* Parliament passes "There shall be an early election" with at least 2/3rds of all Parliamentarians in favour (e.g. at least 433 votes in favour)
John Major's government lost an important vote, so Major tabled a vote of *confidence* the next day, to get his own party to agree his government was doing the right thing. That vote passed. If it had not passed, the newspapers would be like "oooh...." and Parliamentarians would be like "what next?" and he'd be expected to request a new election. Now, nothing would happen, like when May failed to pass her meaningful vote on Brexit. But then when the Opposition got their turn, they could choose to put in an explicit Vote Of No Confidence (as Labour did), and if it passed (which it didn't in March, but who knows in the future) there'd have to be elections. | c0f79d0b-0ebf-4283-b51d-9cf108a1dbf0 |
cjagdk | How Do Military Operations Get Named? | I think I read somewhere it's a random generator. After all, if you're job is to think of cool names about "the death ray fired at the sun" you as a human may inadvertently reveal details of the project subconsciously, like Operation Ray-Ban, Operation Icarus, Operation SPF3000, Operation Lantern Archon. Etc...
A computer prefilled with wordlists (usually with heroic or patriotic, sfw words) won't accidentally slip. A newly designed plunger for toilets may be Project Ovation, where as the Deathstar is deemed "Operation Velvet" since the computer doesn't know the difference between death stars and plungers. And the exclusion of NSFW language prevents the exact scenario of "Your son died serving his country in Operation Buttmunch for the Shitstain campaign" | 7c7dd9f0-783f-457a-87e1-756e9624e4cf |
cjahac | How do scientists estimate the age of a very old animal ? | The shark you're thinking of was a [greenland shark](_URL_4_), and was part of a study that looked at almost 30 individuals ([Nielsen et al. 2016](_URL_6_)). These researchers took samples from the lenses of the sharks' eyes to estimate their ages by measuring the types and amounts of carbon. The reason for using this particular tissue is because eye lenses pretty much never change once an animal is born, and so while other tissues can get renewed, eye lenses are the same age as the animal itself. To ELY5, most carbon is not radioactive (carbon-12), but occasionally, though both natural and human causes, radioactive carbon-14 is made. The amount of carbon-14 in the atmosphere changes over time, but we can study historical levels by looking at various recent fossils, ice cores, etc. The authors of this particular study used two strategies to estimate age based on carbon 14. First, there is a very easily measurable signature of higher carbon 14 in the atmosphere as a result of human nuclear testing in the 1960s. This is known as the "[bomb pulse](_URL_3_)", and it makes it easy to tell if a shark was born before or after 1960 at least. Then, for sharks that were older than this (which was almost all of them), the researchers used an [established dataset of carbon-14 values](_URL_7_) to estimate what time frame was most likely for the sharks to have been born in. Additionally, it helps a lot that these sharks grow continuously throughout their lives, so it's easy to roughly guess the age of a shark based on its size. The sharks in their sample form a [pretty nice curve](_URL_1_) showing the relationship between size and age. Though it should be noted that there is a pretty huge range on the oldest estimates (392 +- 120 years).
In contrast, measuring the age of the clam you're thinking of (an [ocean quahog named "Ming"](_URL_8_)) was much easier. Some clams grow faster or slower depending on the time of year which leads to [growth rings](_URL_5_) in their shells just like a tree. Carbon dating was also used as a separate method to double check this, and similarly agreed on this age within a couple years ([source](_URL_2_)). As a side note, this particular clam was actually discovered as part of a larger study ([Butler et al. 2012](_URL_0_)) that was looking for signatures of environmental change in clam shells going back over 1,000 years. | a3fddd78-ba87-4b20-8212-a5754f76333f |
cjam5x | Why are children viewed as more of a financial burden than they used to? | The expenses that have outpaced inflation the most are those that children require. Health care, housing, education. It can cost tens of thousands just to have a pregnancy and delivery. | e584e09e-dfcf-4a1b-9a17-774296bb1a35 |
cjapdi | How do tower crane counterweights keep from falling out? | In the image you have linked you can clearly see the retaining bolts coming out of the sides, this stops them slipping through. | c65898f4-5d9a-4407-b0f3-3e24d23b3c84 |
cjawoh | Why are male children more likely to inherit or surpass the height of their parents over their female siblings? | Oestrogen closes your growth plates at the ends of your bones, so when girls hit puberty they stop growing shortly afterwards. Boys, who produce much less oestrogen keep growing for much longer and so can reach their full growth potential | c8260131-ba03-41b1-b9f2-ed76986a255c |
cjb621 | If your brain can remember memories from a very long time ago out of nowhere, why is it so hard to trigger your brain to remember things from as recent as yesterday? | Our brain remembers different things very differently, and we have many different types of memory. Explicit memory is one of the two types of long-term memory that allows us to remember things like life-events and facts. This type of memory is conscious which means that you have to make a conscious effort to remember things. Mundane things from yesterday are usually not worth the effort to consciously remember them, so you just forget them.
You can sometimes recall them by remembering less mundane things like where you were, and why, and using your logic to figure out the rest.
I'm no neuropsychologist, but I don't think we know quite yet why our brain acts like this. | a4c19526-1a6a-4a6c-b969-c300a48c15d1 |
cjb8su | Why do we only ever see one side of the moon? | The Moon spins once every month or so.
It also orbits around the Earth once every month or so.
The two periods are the same because the Moon is tidally locked to Earth, meaning the Earth's gravity pulled on the Moon until it stopped rotating relative to Earth.
Bonus fact: the Moon is doing a similar thing to Earth and had already extended the length of an Earth day to maybe twice what it used to be, but because it's so much smaller it'll probably be launched into interplanetary space - by the same interacting - before an Earth day is the same length as a Moon day/orbit. | ee5673af-5553-42fa-ab8e-3d265f1c71a9 |
cjbcoo | Is that spinning circle of leaves that spins around a few times technically a tornado? Why does it happen? | The way air moves can create a 'vortex' (like water spins as it goes down a plughole) the leaves actually make the vortex seeable. Vortexes of wind happen pretty often. | 8c02d919-6ad0-4b0e-bd2d-ad95b4ff732f |
cjbgfm | Why does the key of a song playing on a set earphones change when the earphones are at some distance from the ears? | Higher frequencies get dampened harder over the same distance.
Additionally, you can only hear sound thats at least a certain loudness.
Headphones are low-power speakers and if you increase the distance high frequencies seem do drop out because the fall under that threshold.
The last thing to disappear if you increase distance is bass. | 80a13fc7-18e1-4862-af0d-6ed49fb57bf4 |
cjbh1x | Why are some soldiers wearing pixelated camouflage? | Under certain conditions the pixelated/digital camo does a better job at breaking up the lines/outline/silhouette of the soldier.
The point of camouflage is not only to match the background colour of the soldier's environment, but also to break up any easily identifiable lines. If camo was colour matched to the surroundings but still in big stripes, the soldier would still stand out pretty good (depending on lighting conditions etc.)
Old camo schemes were big hand designed "splotches". Good, but smaller more random splotches break up the pattern of the soldier, load carrying vest, gun/ammo etc. better. The newer digital patterns are even better. | bc02ed03-0d6c-437b-aaaf-2f687eaaa667 |
cjbkx1 | Why are Performance Enhancing Drugs in baseball treated much more harshly than in other sports such as football and basketball? | They’re not, all leagues suspend player for significant amounts of time for use of PEDs. Baseball may suspend more games, but that’s because they have much longer season. | 1fb6d319-325d-4e06-b0b6-c9f447b35374 |
cjbptp | How does most peoples limbs grow the same length and size? | Do you mean relative to other people or their own limbs?
There's an average intelligence, physical size, hand size, limb size, etc for humans. Generally people approach this mean.
For individuals, limbs actually vary slightly in length and size. One will almost always be smaller or larger than the other just not noticeably so.
I don't know enough about the biological processes involved so hopefully someone else tackles this and I learn something too. | f552a4a0-2af3-4a7e-98b5-5e97fb57671c |
cjbuqh | How Hong Kong could leave China? | Outside of some type of armed conflict, there is little reason to believe China would willingly give Hong Kong independence. There certainly remains a possibility that HK remains in a type of state within a state situation that it is now, past the date its supposed to, but even then, China does not seem interested in continuing that solution past the point it has to.
As a bit more history. When the British turned HK back over to the Chinese, the reason they did it wasn't that the lease was expiring. The Brits could not give two shits about that. China literally threatened to go to war with the UK over it. The UK wasn't interested in a war with China, so instead the UK negotiated a fairly reasonable to them gradual changeover of HK to Chinese rule. Since then, its been a complicated situation as the changes occur and China is being less than nice with regards to HK and its people's demands.
As of now, there seems to be no interest from the international community to get involved in the HK-China relationship, as that would be direct rebuff to China and everyone wants to keep peace with China to keep trading. | d7b766cf-4828-43c8-93e1-c62db8bb5546 |
cjc0hv | In order for the US government and election system to be reformed, who all would have to act on it and approve of it? (Is it even a feasible hope for the voters?) | Probably a referenda which is then enacted by legislated by Congress and signed off by the President. | 661bbdd1-01d4-46d1-8508-82585932c5cb |
cjc2gn | How do GPS satellites and receivers compute our position without synchronous clocks between them? | If you assume that the receiver have the exact same time as the transmitter then you would only need 3 satellites as you would be able to know the exact distance to each satellite alone just based on the difference in time. However the receiver does not have an accurate clock. But it is accurate enough to measure the time between the signals from two satellites. So it does not know its exact distance to a single satellite but it knows how much closer it is to one satellite then the other. This is why you need 4 satellites instead of 3. In practice 4 satellites is too few to get an accurate position and you need far more in different directions. | e5affbd9-389c-40b8-a66a-bf850e86f017 |