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[
{
"content": "ELI5:How after 5000 years of humanity surviving off of bread do we have so many people within the last decade who are entirely allergic to gluten?",
"role": "system"
}
] |
We don't know. There are a number of theories about this. To clarify, while the increase may be exaggerated by people who falsely claim intolerance when they probably have other health issues (or are hypochondriacs), there is actually an increase in people with diagnosable gluten intolerance. And gluten intolerance is different than celiac. I'm taking here about gluten intolerance. Some possible causes include changes in the gut microbiome and changes in how we process and make bread.
Changes in the gut microbiome are a likely cause/contributor but the causes and effects of that are just stating to be understood, and barely. So I won't go into that too much, but if anyone has questions I may be able to answer.
On the processing side, one interesting theory is that the germ of wheat helps us process the gluten in some way. It has lots of nutrients, vitamins, fats, etc. Modern wheat flour (even most whole grain stuff) is made by separating the germ from the rest of the wheat first, then processing. This causes the flour to keep longer but removes all those nutrients. This is why flour/cereals need to be fortified. However, we only fortify with the vitamins and minerals for which we notice obvious deficiencies. So it's entirely feasible that we are neglecting to add something back into the flour that helps SOME people not develop gluten intolerance. This may be via some immune response or due to changes caused in the gut microbe (e.g. we are no longer giving some micronutrients to a specific bacteria in our gut so it dies out. That bacteria helped us process gluten or a byproduct and without its help we get sick). It's also possible that our body just needs some nutrient in the germ to process gluten efficiently. We really just don't know.
Tldr: shits complicated literally
edit: First, I know the difference between a theory and hypothesis. I was using the term colloquially, which *even scientists* do sometimes.
People seem to have extrapolated way more than they should have from my comment. Like are asking me where to buy bread with wheat germ and how to fix their gut microbes. That's really not how this works. Anybody who gives you an easy answer to your problems is probably trying to sell you something (I'm looking at you, supplement/probiotics industry...).
Until relatively recently we didn't even know bacteria could survive in your gut, so expecting the scientific community to have a solid understanding of the gut microbiome now is absurd. These questions span the fields of nutrition, microbial ecology, microbe-host interactions, immunology, and more. I'm sure there are hundreds of plausible explanations, but we are VERY FAR AWAY from definitively answering most questions related to the gut microbe. We DO know that it affects digestive health, mood, weight, and all kinds of other human physiology. What we don't know is how to bend it to our will or how it causes all of these things. We do know that the answer is complicated. How do different bacteria interact with each other in your gut, and then with your body? We also don't know much about that. But we're learning.
There is a unique soup of maybe 1000 species of bacteria in your gut, and they are mostly different than the species that live in mine. We are just starting to learn how specific individual species of bacteria can affect their hosts. But even with this research, we don't think that it will be the same in everyone.
example: Maybe bacteria A has effect B on me, but it has effect C on you, because I have bacteria Q in my gut and you don't, and bacteria Q is necessary for effect B. Now consider that x 1000 species, and that a genetic component also affects this, and diet and stress levels and fitness also affect this. See where I'm going?
We do know that the gut microbe is influenced by stress, diet, sleep, environmental exposure, your parents, exercise, infection, travel, antibiotics, alcohol consumption, genetics, epigenetics (which is affected by all of these things and more), social habits, sun exposure, etc. Just to name a few. The extent to which these affect each person is probably highly variable. So asking about specific solutions or a quick fix is a waste of time, especially on the internet. And if you have a shitty diet - especially one high in carbs and sugar - or high stress levels, or you drink a lot, addressing those first is probably a smarter solution than asking about wheat germ and special bread and probiotics (may work in some cases for some people sometimes, and usually not as a "fix" but as a supplement. it's just not well studied enough.) and GMOs (no evidence of them affecting any of this or even a feasible mechanism for how they would).
tldr2: no really, shit's complicated. Something that works for one person may not for another for hundreds of reasons that we don't know much about yet, but are sort-of on the verge of understanding. This is also why the human microbiome is so hard to study. Remember, none of this is well researched enough for there to be standardized advice for anybody outside of the normal "live a healthy lifestyle" advice, and slowly figuring out what makes you feel better. So don't ask for a quick fix and don't trust anyone who offers one. Here are some links about the microbiome and a couple on the microbiome and gluten.
http://learn.genetics.utah.edu/content/microbiome/changing/
https://en.wikipedia.org/wiki/Human_microbiota
https://www.sciencedaily.com/releases/2016/10/161003113009.htm
https://www.scientificamerican.com/article/the-guts-microbiome-changes-diet/
https://www.ncbi.nlm.nih.gov/pubmed/26605783
https://genomemedicine.biomedcentral.com/articles/10.1186/s13073-016-0295-y
http://www.medicalnewstoday.com/articles/309642.php
edit2: yes, non celiac wheat/gluten intolerance exists. some studies have shown that people who claim to have it do not, but that does not encompass all the literature. the key to those studies is that they were looking at SELF REPORTED gluten intolerance, so basically your average "but gluten" person, not people who were medically evaluated and thought to have it. turns out you just have to find the right people to study (who actually have it). just skim this google scholar search and you will see significant evidence of its existence: https://scholar.google.com/scholar?hl=en&q=non+celiac
|
r/explainlikeimfive
|
t3_6efne8
|
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[
{
"content": "ELI5: It's with a heavy heart that we have an announcement\n\nHello ELI5 family,\n\nIt is with a heavy heart and tears in our eyes that we have this announcement to make. We have been informed that moderator Eveanyn has passed away after a years long battle with cancer. We have her family in our thoughts and prayers. We will keep the memory of her and her kindness and strength with us always.\n\nIf you have any kind words you would like to share, please do so in comments. Comments that are not nice will be removed.\n\n\\- ELI5 Moderation Team\n\nIf any of you are interested in donating to a cause in her memory, this charity aligns with the family's wishes. \nhttps://tiltify.com/@magewinter/in-memory-of-ueveanyn?origin=dashboard",
"role": "system"
}
] |
What a beautiful community and one of my favorite subs.
I’m so sorry for the loss that her family and friends feel right now.
Best wishes and blessings 🙏💙
|
r/explainlikeimfive
|
t3_1kfi9hn
|
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[
{
"content": "ELI5: How did we get to the point where laptops and smartphones are in the same price range?",
"role": "system"
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] |
The difference is that most people are buying the top spec smartphones ($1000+), but not nearly as many people buy top spec laptops ($2500+).
|
r/explainlikeimfive
|
t3_cxiwhl
|
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[
{
"content": "ELI5: Stock Market Megathread\n\nThere's a lot going on in the stock market this week and both ELI5 and Reddit in general are inundated with questions about it. This is an opportunity to ask for explanations for concepts related to the stock market. All other questions related to the stock market will be removed and users directed here.\n\nHow does buying and selling stocks work?\n\nWhat is short selling?\n\nWhat is a short squeeze?\n\nWhat is stock manipulation?\n\n[What is a hedge fund?](https://www.reddit.com/r/explainlikeimfive/comments/l6ptb7/eli5_what_is_a_hedgefund/)\n\nWhat other questions about the stock market do you have?\n\nIn this thread, top-level comments (direct replies to this topic) are allowed to be questions related to these topics as well as explanations. Remember to follow all other rules, and discussions unrelated to these topics will be removed.\n\n**Please refrain as much as possible from speculating on recent and current events.** By all means, talk about what has happened, but this is not the place to talk about what will happen next, speculate about whether stocks will rise or fall, whether someone broke any particular law, and what the legal ramifications will be. Explanations should be restricted to an objective look at the mechanics behind the stock market.\n\nEDIT: It should go without saying (but we'll say it anyway) that any trading you do in stocks is at your own risk. **ELI5 is not the appropriate place to ask for or provide advice on stock buy, selling, or trading.**",
"role": "system"
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Hopefully this is helpful. I work in the stock market and my little brother asked me to explain what was going on. Here was my response:
Let’s say GameStop has 100 shares outstanding currently trading @ $20 per share (so if you own 1 share, you own 1%, 25 shares = 25% and so on)
That’s it. There are only 100 shares of GameStop. Throughout the day people are constantly buying and selling these shares for one reason or another (that’s why the stock price moves up and down constantly)
Now, typically when you think about making money in the stock market you typically think “buy low, sell high” 📈. In other words, buying Amazon when it was cheap, and now it’s worth 💰 💰 💰. In this case you would be speculating that the stock price of Amazon will go up ⬆️ in the future
- *fun industry term: you are “bull-ish”*
Here is where the short selling comes into play.
Let’s pretend You have a hedge fund. Alec’s hedge fund manager looks at GME (GameStop) and says “I think GME is over valued, it really should only be trading at $15 per share, not $20 🤔 “
In this situation, He is speculating that in the near future, the GME stock price will go down (to $15).
- *another fun industry term; he would be “bear-ish” on GME*
Now since the hedge fund manager thinks GME’s stock price will go down, He is going to try to make money on that guess by short selling (shorting) the stock.
To short the stock The manager is going to *borrow* some shares from someone else, bob, and sell them at the current market price (which is $20).
Let’s say he borrows 10 shares (total of only 100 remember) and sells them at the New York stock exchange for $20. He made $200 ($20 x 10 shares)
A while later, GMEs stock price suddenly dips (fun industry term: “down ticks”). It is now trading at $15.
Alec’s hedge fund manager was right! now don’t forget, we borrowed the shares from somebody else so we have to give those back. Alec’s hedge fund manager goes to the New York stock exchange and buys 10 shares @ $15 and returns those to the lender.
Alec’s hedge fund made $50 on that trade total (this is called “PnL”).
So the full life cycle:
- *Borrowed 10 shares from “bob”*
- *Sold 10 @ $20 in the market*
- *Bought 10 @ $15 in the market*
- *Returned 10 shares to “bob”*
Total profit = (10 x $20) - (10 x $15)
Okay.... so now onto what is actually happening with GameStop.
Let’s keep the example the same. GameStop has 100 total shares outstanding.
Now a bunch of hedge fund managers all think the exact thing that Alec’s hedge fund manager thought so they all short the stock with the expectation that the price will “downtick” in the future.
Here’s the thing.... someone on Reddit pointed out that despite the fact that GameStop only has 100 shares available at any given time, there were actually 125 shares on loan to cover short sales.
I know this part is confusing, which it should be. That doesn’t make sense mathematically. How can you have more shares loaned out than available? I’m going to gloss over those details and just say that it is possible, and does happen on occasion.
Now when you have a stock that is over shorted like this, you have one major risk, which is called a “gamma/short squeeze” . It does not occur often.
In a gamma/short squeeze, there are more shares loaned out than available. That is because all of those hedge fund managers thought the price would go down and got greedy and tried to make as much 💰 as possible and over borrowed assuming they would be able to cover it. But, someone pointed that out on Reddit, and was able to get that information to go viral. Now with all of these new people buying the stock, it forced the stock price up, very quickly (supply and demand).
Just like in the example, these hedge fund managers had to return the shares to the lender... the problem is, the stock price has gone up so much that if they have to “close their position” they’ll lose a fortune.
- *Example: I sold 10 @ $20 = $200*
Instead of going down; the stock price went up to $400. I have to return the stock to the lender and the only way to do it is to go buy it back. So:
- *I buy 10 @ $400 = $4,000*
- *PnL = +$200 - $4,000*
instead of making money; I lost $3,800.
This is basically what is happening with GME on a much bigger scale
Edit 1:
Lots of people asking about the “loan”. It’s not really a loan in the way that you’re thinking. When you execute an order to sell a share, you are required to Mark it as either “long” or “short”. What this really means is, do you “have” the stock right now in your bank account, or are you “able” to get it easily. So theoretically, everyone could be marking their orders as short sales, assuming the shares are easy to borrow and readily available, except, as the price goes up, people panic and start buying them all up and there aren’t enough to go around. This in turn drives the price up further. Hence the “squeeeeeeeze”
Typical settlement of a trade occurs t+2. In other words, you’re required to deliver the shares you sold short to the counter party within two business days of execution
Edit 2:
for those asking about option expiration:
An option as like a coupon. It gives the coupon holder the right to buy or sell stock, at a given price, on a given date.
Think about it this way. If I think that the stock price of GME is going to go up in the near future, I can buy a coupon (technically a call option) that gives me the right to purchase the stock for a set price at a later date. So if GME is @ $20, I may buy a call option that gives me the right to buy GME stock for $20 per share exactly one month from now (expiration). The idea is that within that time frame; the gme stock price will increase, thereby making my coupon valuable because it allows the owner to buy at a discount.
On the other side, you have someone who “writes” the contract. Essentially sells you the coupon. Let’s say GameStop is trading at $20, and you buy that $20 coupon. Well now, GameStop is trading at $400. So if your expiration is tomorrow you can “exercise” it, and the writer is required to deliver your shares for the agreed upon price, $20. To do that, they’ll probably have to go out and buy it at these exorbitant prices
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r/explainlikeimfive
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t3_l7ckr5
|
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[
{
"content": "ELI5: So how does the the human brain ignore the second the?",
"role": "system"
}
] |
We don't actually read every word in a sentence. Our brains pick up the patterns and fill in the blanks as we skim along the text, which greatly increases our reading speed while doing very little to reduce comprehension.
We do it with just about all sensory input, as well. We blank out while driving but still reach our destinations with no incidents, we tune out smells pretty quickly (no matter how bad the smell is), we tune out physical sensations (you're now aware of how your tongue is resting in your mouth, also you're breathing manually), we hit that autopilot button at work and just coast through it while thinking about the grocery shopping, etc.
It's probably an evolutionary trait that evolved from a need to be vigilant against **unique sensory input**, like sudden movements and noticing things that aren't supposed to be there. We're good at recognizing patterns, and tune things out to reduce overall taxation from sensory inputs so we can instead focus on novel inputs.
Small edit: I'm an English tutor, and one of the practices we use to catch those kinds of mistakes is to read the whole text backward. Doing this tricks the brain into not recognizing the speech patterns and causes it to focus on each word.
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r/explainlikeimfive
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t3_g29knw
|
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[
{
"content": "ELI5: Why can people walk many miles without discomfort, but when they stand for more than 15 minutes or so, they get uncomfortable?",
"role": "system"
}
] |
I work at a vein surgeon's office. I actually asked him this.
Basically, when you are standing, blood flow slows and "pools" in your legs due to gravity. But when you walk, your muscles contract and push the blood in your veins and vessels back up into your upper body.
On the side note, seasoned military personnels are able to stand at ease for long periods of time because they are actually swaying back and forth very slowly in micro-movements to contract their muscles and relieve the tingling and numb sensation you get when you keep standing for long periods of time.
Edit: As others have suggested, not locking your knees is also key
Edit 2: As others have mentioned, micro movements could be flexing your calves, distributing weight back and forth between your heels and toes, wiggling your toes, etc.
Edit 3: If you have persistent leg problems even without prolonged standing and even after conservative measures (compression stockings, exercise, etc.), I would recommend getting a referral to a vein specialist from your PCP (in the US) to get it properly treated. You may just have bad veins.
Whoa! My very first gold. Thank you stranger 😝
|
r/explainlikeimfive
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t3_6joszt
|
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[
{
"content": "ELI5: There are infinite numbers between 0 and 1. There are also infinite numbers between 0 and 2. There would more numbers between 0 and 2. How can a set of infinite numbers be bigger than another infinite set?",
"role": "system"
}
] |
I think the problem is you are thinking of "infinite" to be "a very big number". It is not a very big number, it's a different kind of thing. A similar problem exists with zero, in that it's not just "a really small number", it's actually zero. For example if I take a really small number like 0.0000001 and double it, I get 0.0000002. If I take 0 and double it, I still get zero. 2x0 is not bigger than 1x0. If I have an infinite number of numbers between 0 and 1, then they are separated by 0. If I double all of those numbers, then they are separated by 2x0, so they are still separated by 0.
Edit: thanks for the kind words and shiny tokens of appreciation. This is now my second highest voted post after a well timed Hot Fuzz quote, I guess that's what reddit is like.
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r/explainlikeimfive
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t3_h9yh9l
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[
{
"content": "ELI5 Why is 12 hour time even taught? Wouldn’t it just be easier to remember 13:00 instead of 1:00pm?",
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}
] |
12 hour time is a *very* ancient system that traces back to the Mesopotamian empires.
They had a cultural fixation on the number 12, used a base-12 numerical system, and divided up most things into 12ths whenever possible - including day and night.
The 12 hours of day and 12 hours of night system spread throughout Europe and the Middle East and has defied multiple attempts to change it over the centuries.
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r/explainlikeimfive
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t3_hsa8kn
|
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[
{
"content": "ELI5 remembers u/bossgalaga\n\nHi Everyone,\n\nWe have come to learn some very sad news recently, u/bossgalaga, the founder of r/Explainlikeimfive, has unfortunately passed away. In his honor we wanted to post the links of two charities that were dear to him:\n\n[The Immune Deficiency Foundation](https://primaryimmune.org/waystogive)\n\n[The Institute for Effective Education](https://www.tiee.org/about/)\n\nWe are forever grateful for what he has created and hope you will consider supporting charitable organizations as he did. As our regulars may recognize this post is out of character for us but as a mod team we felt these circumstances were unique. This post will stay up for a week, and we will include links to those charities in our wiki.\n\nAdditionally, it has come to our attention that u/bossgalaga made a post in /r/askreddit on July 28th, 2011 (ten years ago yesterday) asking if people would be interested in a sub dedicated to, \"...ask(ing) questions that some people might find obvious -- and to do so without fear of being downvoted, made fun of, or ignored.\" This, of course, led to the start of r/explainlikeimfive. If you're interested in reading that post, [you can do so here.](https://old.reddit.com/r/AskReddit/comments/j2a9k/would_anybody_be_interested_in_a_new_subreddit/)\n\nThank you all for the kind words thus far. u/bossgalaga's friends and family certainly will appreciate them.",
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RIP. This sub was one of the first I started reading on reddit way back when. He came up with a great idea that really showed how cool this website could be.
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r/explainlikeimfive
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t3_otzyon
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[
{
"content": "ELI5 why do humans need to eat many different kind of foods to get their vitamins etc but large animals like cows only need grass to survive?",
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] |
In addition to the 'efficiently breaking down grass' thing, and the 'they eat a variety of plants' thing, there's also the fact that species typically evolve the ability to make vitamins that they can't get easily in their diet. For example, humans make vitamin D because there aren't many food sources of it, but we can't make vitamin C, but can find it in food. But other species can make their own vitamin C.
It's a trade off between needing to find a variety of food and not needing the cellular machines to make more stuff.
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r/explainlikeimfive
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t3_il5ptb
|
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[
{
"content": "ELI5 If diamonds and other gemstones can be lab created, and indistinguishable from their naturally mined counterparts, why are we still paying so much for these jewelry stones?\n\nEDIT: Holy cow!!! Didn’t expect my question to blow up with so many helpful answers. Thank you to everyone for taking the time to respond and comment. I’ve learned A LOT from the responses and we will now be considering moissanite options. My question came about because we wanted to replace stone for my wife’s pendant necklace. After reading some of the responses together, she’s turned off on the idea of diamonds altogether. Thank you also to those who gave awards. It’s truly appreciated!",
"role": "system"
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] |
Marketing and monopoly. Diamonds are not unique or rare on this planet. The DeBeers corporation has a long standing monopoly, and an incredible marketing campaign stressing that you should spend 2 months salary on a ring if you really love your future wife.
Truth be told, lab grown diamonds are so perfect at this point, that DeBeers is spending millions trying to figure out how to tell the difference.
|
r/explainlikeimfive
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t3_kcpsov
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[
{
"content": "ELI5: How come you can be falling asleep watching TV, then wide awake when you go to bed five minutes later?",
"role": "system"
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The brain is like a group of people talking to each other. When you're watching TV, the part of your brain that watches TV says "Shut up guys, I'm watching TV," so you can focus without thinking about cake or math. As a result, the others sit silent, grow bored, and fall asleep, until only the TV watcher part of the brain is left. Left by himself, he too gets bored and falls asleep.
When you're in bed, assuming you aren't counting sheep or something, the entire brain is kind of in free time mode, and any part of the brain can speak up if it wants to. They start talking to each other, and even if one of them starts to drift to sleep, the others wake it up either by deliberately talking to the sleepyheads or just being noisy. Eventually more and more of the parts of the brain fall asleep from sheer exhaustion no matter how loud the others are, and eventually the last one passes out and you are asleep.
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t3_6iowpi
|
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[
{
"content": "ELI5: How did Germany stop being Nazis after the end of WWII? Did everyone just \"snap out of it\" after Hitler's death?",
"role": "system"
}
] |
There were a lot of politicians the Nazis had arrested or removed from office. The first leader of West Germany had spent time in a Nazi prison. The US and the Allies had a specific 'De-Nazification' program they used. It included things like forcing Germans to visit the death camps.
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t3_oekyts
|
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[
{
"content": "ELI5: The Panama Papers\n\nPlease use this thread to ask any questions regarding the recent data leak.\n\nEither use this thread to provide general explanations as direct replies to the thread, or as a forum to pose specific questions and have them answered here.",
"role": "system"
}
] |
When you get a quarter you put it in the piggy bank. The piggy bank is on a shelf in your closet. Your mom knows this and she checks on it every once in a while, so she knows when you put more money in or spend it.
Now one day, you might decide "I don't want mom to look at my money." So you go over to Johnny's house with an extra piggy bank that you're going to keep in his room. You write your name on it and put it in his closet. Johnny's mom is always very busy, so she never has time to check on his piggy bank. So you can keep yours there and it will stay a secret.
Now all the kids in the neighborhood think this is a good idea, and everyone goes to Johnny's house with extra piggy banks. Now Johnny's closet is full of piggy banks from everyone in the neighborhood.
One day, Johnny's mom comes home and sees all the piggy banks. She gets very mad and calls everyone's parents to let them know.
Now not everyone did this for a bad reason. Eric's older brother always steals from his piggy bank, so he just wanted a better hiding spot. Timmy wanted to save up to buy his mom a birthday present without her knowing. Sammy just did it because he thought it was fun. But many kids did do it for a bad reason. Jacob was stealing people's lunch money and didn't want his parents to figure it out. Michael was stealing money from his mom's purse. Fat Bobby's parents put him on a diet, and didn't want them to figure out when he was buying candy.
Now in real life, many very important people were just caught hiding their piggy banks at Johnny's house in Panama. Today their moms all found out. Pretty soon, we'll know more about which of these important people were doing it for bad reasons and which were doing it for good reasons. But almost everyone is in trouble regardless, because it's against the rules to keep secrets no matter what.
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t3_4d8rta
|
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[
{
"content": "ELI5: Addressing Concerns Regarding Reddit\n\nAllegations have come to light regarding the recently hired Reddit admin, who shall not be named, that she willingly associates with child abusers and rapists. Additionally, there is evidence that Reddit is abusing their platform to stifle legitimate discussion of these allegations. More information can be found [here](https://www.reddit.com/user/Blank-Cheque/comments/mbmthf/why_is_this_subreddit_private_see_here_for_answers/).\n\nGiven the seriousness of this issue, we are joining other subreddits in asking for Reddit's administration to explain their justification for hiring her. We would also like to see her removed, as we feel that her employment with Reddit stands against the values that Reddit users believe in.\n\nIf Reddit does not remedy this situation and/or offer an adequate explanation for their actions by 2021/03/26 12:00 GMT, ELI5 will be set to Private in protest.\n\nWe hope our users will support our actions and stand in solidarity with us and the other subreddits that are looking for answers.\n\nEdit: please do not award this post.",
"role": "system"
}
] |
[https://www.reddit.com/r/announcements/comments/mcisdf/an\_update\_on\_the\_recent\_issues\_surrounding\_a/](https://www.reddit.com/r/announcements/comments/mcisdf/an_update_on_the_recent_issues_surrounding_a/)
Hi Everyone, mission accomplished, we will be unsticky-ing this post now
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t3_mchcni
|
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[
{
"content": "ELI5: If there is no cellphone signal, how does the \"emergency calls only\" mode works?",
"role": "system"
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] |
Your phone is allowed to use any network its physically capable of using for emergency calls, whereas normally it can only use networks you've paid to use E.G. signals from a Verizon tower.
EDIT: Looks like I was partially wrong. Quoting /u/psfilmsbob "Every carrier has roaming deals with other carriers who use the same signal, meaning your AT+T phone will work on T-Mobile towers, vice-versa. Same with every major carrier."
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t3_7mb35n
|
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"content": "ELI5: Why is it, that you can eat a 2,000 calorie meal, and in theory, you shouldn't need calories again until the next day, but you can be hungry again 6-8 hours after you finish eating? Is your body just not capable of actually processing that many calories?\n\nI think the title kind of says it all, but I watched a video of someone eating a 2.1k calorie burger, and his friend said, good now you won't need to eat for 24 hours and they laughed, then I thought, \" wait why is it that you would be hungry again after 6-8 or so hours, is our body that inefficient with those calories? Does this mean that when you eat over a certain limit of calories you body just puts the rest into waste and some into fat? How does it work?\n\nUpdate: Wow thanks for all the upvotes, awards, and comments. I really appreciate all the new information and help on this topic.",
"role": "system"
}
] |
Your body is like a steam engine. The fireman gets a load of coal (food) and either shovels it into the engine (your body's metabolism) or shovels it into the [tender](https://www.lionelstore.com/LionelStore%20Product%20Images/636847-1.jpg) (your fat reserves).
Hunger is the fireman saying "hey, just so you know I'm not getting any coal right now... could be an issue." He doesn't care that the tender has plenty, just that no more new stuff is coming in.
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t3_ifgmcr
|
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{
"content": "ELI5: what is the reason that almost every video game today has removed the ability for split screen, including ones that got famous and popular from having split screen?",
"role": "system"
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] |
3 Main reasons:
1. It takes a lot of extra processing power to generate the split screen aspect.
2. Its development work they would rather put towards their more lucrative multiplayer (usually with microtransactions)
3. they sell more copies of the games to groups of friends who want to play it.
Now all of those are horseshit reasons, and I want my couch coop back, but still. I would (and do) support games with couch coop, like borderlands, lovers in a dangerous spacetime, speedrunners, etc. I recommend you do the same.
Also fuck Halo 5.
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t3_6o4cgc
|
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[
{
"content": "ELI5: How does your body burn 2000 calories a day, but you have to run a mile to burn 100 extra?\n\nBasically the title. I saw this thing about how much you have to exercise to burn off certain foods and was wondering how your body burns so many calories by doing nothing.",
"role": "system"
}
] |
You're not doing nothing. Your heart is beating, your brain is processing, your eyes and ears are collecting information, your muscle tissue is idling, awaiting command. You're maintaining a core temp of precisely 98.6F.
None of this is free, you'll consume 1500-2500 calories a day simply keeping the biological lights on.
We're highly efficient runners, and burn little energy to do so compared to many other animals.
|
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t3_eluost
|
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[
{
"content": "ELI5: Went on vacation. Fridge died while I was gone. Came back to a freezer full of maggots. How do maggots get into a place like a freezer that's sealed air tight?",
"role": "system"
}
] |
There was an egg on something before you even put it in there. Usually they just can't hatch because of the temp. At room temp they can hatch.
|
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t3_6i881n
|
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{
"content": "Eli5: If ants love sugar, and bees make honey, why aren’t bee hives constantly attacked by ants?",
"role": "system"
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] |
Ants are constantly trying to attack beehives. Other bees and insects will also try to attack the beehives. This is why a large number of bees is dedicated to protecting their hives from these intruders.
|
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t3_kzrxay
|
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[
{
"content": "ELI5: Why do traditional cars lack any decent ability to warn the driver that the battery is low or about to die?\n\nYou can test a battery if you go under the hood and connect up the right meter to measure the battery integrity but why can’t a modern car employ the technology easily? (Or maybe it does and I need a new car)",
"role": "system"
}
] |
The technical people answering are technically correct, that a voltmeter would indicate the voltage of a battery, but they’re missing what OP is after: when won’t a battery work anymore? In other words, they are wondering “why can’t I know the health of my battery?”
With car batteries (the 12V lead acid type) the voltage isn’t really a good indicator of health. An old dead battery can read ~12V just fine. It would likely power most lights and equipment, too. The real test of health comes when trying to start the engine; the “load” test. An old battery can read 12V until asked to turn the starter, then immediately drops to an unusable voltage.
The simple answer is that traditional 12V car batteries do not have the sophisticated tech to indicate their health like, say, laptop batteries. Nor is there a good way to test the health except for hooking the battery to a load, which isn’t an easy thing to build into a car’s circuitry. Basically, starting the engine IS the load test.
Edit: To all those asking why a load tester couldn’t be added into the hardware or software of a car: it could. Nearly anything is possible with time and money. But I agree with the comments from those in the industry; it comes down to three basic things:
1) Added cost (automotive margins are very thin)
2) Added complexity and engineering effort for nearly no return (exactly who would truly want this?)
3) Service side (auto companies do not wish customers to have to think about maintenance beyond knowing to take the vehicle in when the light turns on)
Edit 2: Since this blew up from my original simple answer, we’ve attracted the attention of my more astute engineering colleagues. It appears my answer is a little dated. The fact is that this diagnostic capability DOES exist in more modern vehicles. But just as auto companies have chosen to shroud engines in giant swaths of plastic to hide the ugly technical bits, so have they chosen to hide most of these diagnostic abilities from the consumer behind a simple light or “Service Soon” message. Good discussion!
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t3_jz2tg3
|
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[
{
"content": "ELI5: Why aren't power lines in the US burried underground so that everyone doesn't lose power during hurricanes and other natural disasters?\n\nSeeing all of the convoys of power crews headed down to Florida made me wonder why we do this over and over and don't just bury the lines so trees and wind don't take them down repeatedly. I've seen power lines buried in neighborhoods. Is this not scalable to a whole city for some reason?",
"role": "system"
}
] |
Hi! I'm actually an estimator for a large electrical contractor, so I think I can comment on this pretty accurately.
In large cities you're correct, there's a reason you don't see power lines draped across buildings in Manhattan. And even more affluent neighborhoods will have the lines buried. But there's one enormous reason that ALL lines aren't buried: cost.
Now this answer had been given, but there's some details you might find interesting.
The first is initial installation. Most underground cable at distribution voltage (4kV to about 35kV but that definition fluctuates) is installed in buried conduit, and basically every construction company can tell you that digging sucks. Even with a geotechnical report, some areas of the country are a total crapshoot as to what you'll find 3' down. In parts of VA it might be the water table, in parts of ID it might be lava rock. Usually the ground is either too soft and the hole/ trench doesn't hold up, or too hard and it takes forever to dig. Either way that means money.
Digging also isn't very pretty, and most places have lots of rules regarding how you dig, when you dig, what you do with the spoils (dirt you dig up) and what you have to do to clean up afterwards. If you dig in the middle of nowhere this isn't bad, but God forbid you're in the rich part of town. Then on top of all this money you spent following the rules you now have to spend another big pile fixing landscaping (ya know that bush you dug up? The fourth one from the end that was almost dead? Yea, that was my great great grandmother's golden bush of infinite happiness! You owe me $5000 for it! No an almost identical bush isn't good enough!).
Not too mention underground conductor is more expensive. The conduit it goes into is an added cost, but it pales in comparison to the price difference between underground wire and what you'd spend on overhead wire for a similar amount of current. Additionally this wire has to hold voltage that is desperately trying to release itself into the surrounding earth, so if you nick it when pulling it in, or damage the insulating jacket in some other way, congratulations you get to pull that wire in again! Because that electricity will arc that gap and the line won't work.
If that happens later on down the road, it's also much more difficult to diagnose and fix. With an overhead line, you can usually tell what's wrong (hint: what parts that should be in the air are now on the ground?) But with underground lines you have to drag out the thumper.
The thumper is a piece of equipment that applies a voltage to a line. The voltage goes higher and higher until it arcs through damaged insulation and makes a thump sound underground. Then a worker has to locate the fault (damaged piece of line) by walking the route of the line and listening for the thump. Now newer equipment is fancy enough to help you get pretty close without much work, but there's still a lot of experience and good luck to finding the fault quickly. By the time you add in the cost of the thumper, the crew's time to actually dig up and fix the line, and the outage time for the customers being fed, you're taking a pretty penny.
Not to mention, mother earth is not kind. If you go to more remote places you can find lines that have been around 60 or 70 years. Not going to find many underground lines that old.
There's also the fact that adding capacity to overhead lines is easier in most cases, but that's a bit too nuanced for this post.
And finally, electricity is pretty easy to move overhead. Water, oil, gas, and sewage are not. In most places the ground where it would make sense to bury power lines is *crowded* and most of those companies don't want high voltage anywhere near their stuff. Hell they don't even want the pole in the ground because most of the poles are grounded. But any company that will even let you bury near them is going to, at minimum, want an inspector on site while you build, and you get to pay his wages while he's out there. Most companies would rather take you to court than let you build though.
So most of the time, high lines are where it's at!
Edit: All of my experience is in North America. I don't know why Europe manages to get everything underground, but as I mention below I expect its a combination of denser urban areas and government regulation. Some places in the US are experimenting with that, but others probably won't for quite some time.
/u/thekbob linked a great study here: http://www.eei.org/issuesandpolicy/electricreliability/undergrounding/Pages/default.aspx
That goes a lot more in depth about why underground electric utilities are better at some things, and still unlikely to catch on in the states.
Also, I may have given enough information for some really dedicated soul to deduce who I work for. For the record I am not an official spokesperson for any company, any opinions expressed here or in other comments are solely my own and do not reflect the opinions of any other entity.
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t3_6zgo04
|
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[
{
"content": "ELI5: How can large chains (Target, Walmart, etc) produce store brand versions of nearly every product imaginable while industry manufacturers only really produce a single type of item?",
"role": "system"
}
] |
Because they don't actually make it.
Costco doesn't make "Coscto Whisky" Costco has a contract with (it's not but for ease of names) Jack Daniels. And again for ease I will use "Bottles" not "Barrels"
If Jack Daniels sells their whisky for $20 a bottle, say it costs them $10 to produce. Costco says "We want to buy your whisky at $15 per bottle, but we will order 10,000 bottles. We're going to resell it as Costco Whisky"
Jack Daniels says "Sure thing, but here's an Non-Disclosure Agreement. You cannot tell anyone Costco Whisky is made by Jack Daniels."
Jack Daniels may only make $5 per bottle instead of 10 but they just sold 10,000 bottles. Costco paid $15/bottle, cost the $1/bottle to re-label it and they sell it at $18/bottle.
So it's cheaper to buy costco & they still make money. They then do this with many other products.
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t3_6p83n3
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[
{
"content": "ELI5: Why does \"Hoo\" produce cold air but \"Haa\" produces hot air ?\n\nTried to figure it out in public and ended up looking like an absolute fool so imma need someone to explain this to me",
"role": "system"
}
] |
When you do a "hoo", the air is coming out from a very small opening which gives it a higher chance to mix with the air around it and cool down.
When you do a "haa", the air is coming out at a larger volume and needs more time to cool down.
**Edit**
Put your finger right in front your mouth when doing a "hoo" and you will sense that it's actually just as hot as a "haa", but cools much faster a few cms away.
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t3_d4j294
|
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[
{
"content": "ELI5: Why is it that Mandarin and Cantonese are considered dialects of Chinese but Spanish, Portuguese, Italian, and French are considered separate languages and not dialects of Latin?",
"role": "system"
}
] |
There's a saying in linguistics: "A language is a dialect with a flag and an army."
The field of Linguistics does not actually define what is a "language." Linguistics definitely has the concept of a dialect, and can discuss whether two groups of people speak the same dialect or different dialects. It has concepts of things like mutual intelligibility, i.e. can native speakers of two dialects understand each other. But the idea that two dialects are part of the same "language" is a question that linguistics entirely cedes to the field of politics.
So, the answer to your question: China considers itself a single political unit, and they place a high value on considering themselves unified. France, Italy, Spain, and Portugal consider themselves distinct political units from each other, and modern Italy considers itself distinct from the Roman empire.
It's also worth noting that people from different regions in Italy sometimes can't understand each other, because dialects of Italian have a very large spread. Again, they're considered the same language because Italy wants to perceive itself as a single unified cultural entity.
Were one of these regions of Italy to become independent, it's likely they would consider their dialect to a language over time, although that process would likely involve doubling-down on the regionally-distinct features of that dialect, and probably having a distinct literary tradition as well. Something like this [already happened](https://en.wikipedia.org/wiki/Norwegian_language_conflict) when Norway became independent of Denmark.
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t3_bezewk
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{
"content": "ELI5: If bacteria die from (for example, boiled water) where do their corpses go?",
"role": "system"
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] |
Hah! One of those things people don't think of! YES excellent question.
Sorry, I work with medical devices, and this is a crucial issue.
So lets say we have a scalpel, right? Simplest medical device there is. There's a number of ways to make it totally(ish) sterile- gases, steam, dry heat, gamma radiation.
But as you ask- the little bacterial corpses are still *there*. Waiting, one presumes, for tiny necromancers.
The problem occurs when you stab someone with the scalpel, preferably in a medicinal way. The bodies immune system works by identifying certain chemical triggers in bacteria, and has no way to know that, for example, the lipopolysaccharide hanging around in someone's heart is not part of a bunch of living bacteria, but the floating corpses of dead bacteria.
The dead byproducts of bacteria are called "pyrogens" because they cause (among other things, such as death) fevers.
Where do they go? Nowhere. Bacteria are small enough that water has completely different properties on their level. Beyond rinsing off gross matter and reducing bacterial load, washing can't do much.
So for things like heart surgery scalpels, there will usually be a second step of "Depyrogenation" This is the process, not of killing bacteria, but of removing the bits left behind so they don't trigger an immune reaction. This varies widely in complexity depending on what you have to depyrogenate- steel scalpels are easier than an injectable drug, for example. Typically, the goal of the process is to so thoroughly break down the biological material left behind.
*ok dang, Fiddling with this post to answer some common questions* There will be more of the apparently popular TimeNotTheMiles Humor, plz don't turn on me like wild dogs k thnx.
**My post on how Depyrogenation can be done**
[here](https://m.reddit.com/r/explainlikeimfive/comments/5640rc/eli5_if_bacteria_die_from_for_example_boiled/d8g6ctk)
**General Note: Endo and Exotoxins are types of Pyrogens**
*For more detail go [here](https://m.reddit.com/r/explainlikeimfive/comments/5640rc/eli5_if_bacteria_die_from_for_example_boiled/d8g9z8v) where u/aliteralmarshmallow u/Saint_Gainz u/checkhorsebattery and u/Chapped_Assets go into detail about endo and exotoxins using incredibly inappropriate words for five year olds- like "lysed", and "amebcytes"*
*Keeping on Chooglin'!*
**Why not make instruments out of antibacterial materials? Or 3D print them?**
If its a metal, you can just heat it. From a strictly technical standpoint, thermal heat is not the most efficient way to destroy the dead remnants of bacteria, but from a cost effective standpoint, it's really cheap. So you might as well use steel. If its a liquid, the issue isn't sterility-sterile is dead germs. Depyrogenation is cleaning up the germ corpses and the deathjuices they spit out in their hate. Where it gets technically tricky is working with things like drugs or implantable substances. IE- stuff that you can't just put in an oven.
**Quick run down on terms**:
*"Cleaning"* a medical device is basically doing dishes-getting blood n bits off the reusable ones. (plz dont reuse single use medical devices that makes regulatory professionals sad 😭)
"*Disinfecting"* is using chemicals to get something purty darn clean.
*"Sterilization"* is killing all* the germs on something
*"Depyrogenate"* is taking bacterial corpses and reducing their remaining structure to a point where your immune system won't recognize it and freak out.
*SALx10^-6 is the typical sterility level for a medical device. one in a million germs/one in a million devices
**are my hands covered in bits of dead bacteria?**
No your hands aren't covered in dead bits of bacteria. They're covered in happy, healthy bacteria.
**Then why wash my hands?? I would like to be filthy, but society....**
Washing your hands removes dirt and debris that carry the nastiest bacteria. Sterilizing your hands is a ridiculous notion however- your hands are made of cells, bacteria are made of cells. Anything that would kill them would kill your cells. Your hands, and literally everything else on the world not currently under direct gamma radiation bombardment, are covered in bacteria.
**Does that mean the Incredible Hulk generates a sterile field?**
Couldn't say for sure, but you get to collect the skin swabs.
**Am I eating Pyrogens? Will I die? Tell....tell Amy I always loved her.**
Pyrogens aren't much of a concern for eating. Your mouth is filled with bacteria, so is your digestive tract, so is your skin, so is everyone you love, so is the air EVERYTHING IS COVERED IN GERMS AHH AHH AHH
Basically,your entire body is covered in and filled with teeming hordes of bacteria trying desperately to eat you alive, so your body is used to dealing with it. Pyrogen reactions are a concern when you put dead-germ bits into places that don't have germs- blood, pleural cavity, brainbox...
Think of your immune systems reaction this way: You walk into your living room and find a DEAD BODY. Is it going to hurt you? No. Do you freak out anyway? Yes.
(Also your wife is named Mary, I'm deeply ashamed of you, *think about your life.*)
**THE EXCEPTIONS** are things like E. Coli, Salmonella ("I barely know Ella!") and botulism. In that case, what makes you poo/die is the toxins left behind by the bacteria. So if you have a piece of rotting meat, you can't just cook it until it is safe, because the toxins are what get you, not the live bacteria. However, boiling CLEAN water (**NOT AN EXPERT ON POTABLE WATER BRAH DRINK AT YOUR OWN RISK** makes it safe to drink because its unlikely (in clean water) that there will be enough toxins (in clean water) to hurt you (drinking clean water well boiled.)
**Um, reusable medical devices?? Like, Grody to the max + 1 4EVA.**
It depends. A lot (**LOT**) of effort goes into making reusable devices safe. A lot of reusable devices have limited re-usability. For example, you *may* be able to reprocess a scalpel a time or two, but eventually, that edge will start to fade, and the surgeon isn't going to whip out a whetstone mid surgery, are you kidding me it's not the civil war.
There are, however, serious issues issues with reusing non-reusable medical devices, particularly things like lumens, catheters, shavers, and it gets gross. It gets really, really, REALLY gross [you don't want to read this but you will anyway and it will haunt you, welcome to my life](https://www.publicintegrity.org/2012/02/22/8207/filthy-surgical-instruments-hidden-threat-americas-operating-rooms)
**One word. LAZERS. *PEW* *PEWPEWPEW* *BZZZ* Murica yahhhhh**
Take a laser pointer. Shine it on your hand. (NOT your eyes, hand) Not much happens. Flesh is tough stuff, and mostly made of water, which tends to boil away under lasering, requiring lots of energy. Surgical lasers are HUGE, and full of all sort of dangerous chemicals. Eye surgery uses lasers because eyes are delicate. Weak. Cowardly.
**What happens to dead bacteria in nature?**
Tiny. Necromancers.
(jk they get et. Bacteria are just little bits of protein. The amino acids that they're made of aren't any larger than the ones that make cow cells.)
**I know that bacteria can steal DNA from each other, can they do this with pyrogens, and will this happen inside my body**
Not a clue, awesome question, someone make an ELI5.
**This isn't a real ELI5! There are words of multiple syllables! You don't get the ELI5s like you used too! I remember I used to go to shelbyville on the ferry, of course, we called it a toot-toot chugalug in those days....**
Ok, the real r/ELI5ForActualFiveYearOldsAndNotJustaRedditMetaphorForSimplifiedExplanations :
Germs are tiny gross things that make you sick, and they can be in WATER! EWWWW How do we kill them? Water gets hot! Real hot! Wow, SO hot! Bubble bubble!
But OH NO the germs left their bodies behind! Now, Timmy (Timmy pay attention) we can DRINK the dead germs without any worries, because we have strong tummies (I KNOW I DON'T HAVE A SIX PACK TIMMY OK I WORK ALL DAY DAMN). But what if you had to do important medicine on a person and open then up to help them? Well, then what can happen is the nasty dead germ bodies can get into someones body! OHHHH NO! Your body is really smart, and knows that germs have special things in their bodies. (Yes timmy, even germs are special. Just like you.) And when your body senses those special things, it goes and attacks the nasty germs- that's what happens when you're sick! (Yes like when you threw up allll over daddy and woke him up. Yes, he did say bad words.)
But your body can't tell that the nasty dead germs are dead! It sees the SPECIAL GERM STUFF and it freaks out! OHHH NOOO! Then you get sick without any nasty germs at all, and that kills people to DEATH.
So people who make stuff for doctors use SPECIAL ways of cleaning Doctor stuff to take away the nasty germ bits, so your body doesn't get scared and die.
No you can't have a cupcake, dinners in half an hour.
(**HAPPY??** )
---*edits about how all y'all are awesome*---
Edit: wow thanks! Um-rude to assume, I know. but if anyone was considering golding me (its happened before) plz dont, I dont use it. Send the money to a charity or something.
Also...how does this have more upvotes than the post? U/doitsarahlee deserves your love too.
Edit:You are all the best. I'm seriously flattered by the amount of interest in a pretty dry subject, and you've all been absolutely awesome- all the replies, PMs have been incredibly kind and genuinely interested.
You give me hope for reddit, and a disgusting amount of Karma. Thank you all!
Hour 18: if you have not experienced Reddit love before, let me [explain.](http://giphy.com/gifs/dog-saint-bernard-G3cYjFpMS2JOw)
Theyre all so friendly....and curious....
Ill try, reddit. For you. For the karma. I've got an Augean stable of love in my inbox though.
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t3_5640rc
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"content": "ELI5: if fruit is sweet to encourage animals to eat it and carry the seeds away from the parent tree, how do lemons and limes fit into this mix?",
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] |
**TL;DR**: *Because lemons and limes are crossbreeds that weren't actually a wild plant, and even if they weren't sweet, their ancestors still had sugars and that made them appealing for creatures to eat.*
Most of the types of "citrus" plant that we grow and sell in produce sections now were crossbred from a mix of only a few original plants. Lemons come from "Citron", a really thick-rinded fruit with a small but sweet pulpy core, and "Bitter Orange", which is what it sounds like. Limes comes from a citrus-type tree called "Micrantha".
But even so, just because they taste sour doesn't mean that animals won't eat and spread them. A lemon DOES have sugars and, in the same way we humans like a little bitterness, animals may appreciate it too. Food doesn't have to taste sweet to be extremely healthy and an easy source of calories.
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t3_86u0qv
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"content": "ELI5: Why does making a 3 degree difference in your homes thermostat feel like a huge change in temperature, but outdoors it feels like nothing?",
"role": "system"
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Because outside you have multiple things that affects the way the temperature feels. A slight breeze or moment in the shade will feel cooler. Humidity or the sun shining on you will make it feel warmer. Inside you don’t feel these variables nearly as often.
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t3_ayshki
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"content": "ELI5: Why do you need a Master's Degree to become a librarian, especially when the median salary is barely above $50,000?\n\nOn Jeopardy tonight, one of the contestants stated that he obtained a Masters Degree online just to become a librarian.",
"role": "system"
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It depends on what type of Librarian you are talking about.
Librarians assistants are generally just the people who learn about librarian functions and are the people who put the books away, do general checkout functions, so on and so forth.
Librarians, are generally like supervisors. They oversee the librarian's assistants and do daily work such as general supervision, overseeing a libraries general functions in addition to just checking out books, and organizing the Libraries overall day to day affairs. Ordering new books, processing new releases, so on and so forth...
Librarian Managers are usually overseeing multiple installations, or even non-traditional library resources. Sometimes Museums will have libraries or specialty function libraries such as University libraries. Also, this is where you will start to get into special functions such as document maintenance, archival and care. Larger institutions such as University libraries have VERY LARGE collections, spanning 100s of thousands of pieces, in multiple different departments, more than 1 single Librarian and their assistants can adequately manage.
Then you have Librarian Directors. When Libraries get so large that they have multiple departments, you need a Director level, who typically will be overseeing the business side of opening and maintaining either large University Libraries, or entire systems of local libraries. Take a single City... You could have 20 or more libraries within a system that serves that city, as well as manages several school library's contents and local municipal libraries. You'll have 1 Director, Several Managers, and at least 2-5 Librarians per library itself.
That level of staffing, needs proper management. So when you are getting your Masters in Library Science, some of the courses are also business management skills as well as advanced Librarians systems classes. Document restoration, special documents care, archival systems... these are not simple procedures that can just be taught on the fly, several years of education is needed to make sure that not only does the library stay properly stocked, but also that you can handle the challenges of maintaining books, relics, artifacts and everything else that may walk in your door.
edit: In addition to my normal post, like I said there are many other positions inside libraries that require specialized training and having someone that has been properly trained is a necessity, regardless of how much you make.
/u/maybeitsmeh -
>Handles copyright, contracts, resources used in courses, assists professors and course designers, has spoken on learning topics and libraries as a part of legislation for the state, has co-authored books, and participates in research.
[...quoted text...]
/u/efs001 -
>I took management, legal issues for librarians, and digital preservation course in addition to the traditional reference, information organization, and collection development. I also took classes in archival description and arrangement, archival appraisal, and metadata which are very applicable to my job. I also help my patrons navigate copyright issues that are quite complex when you work in an archive.
[...quoted text...]
edit 2: Woot! FP of ELI5 w/ top comment. First time ever!
edit 3: WOW! Actual FP! amazing! I've never been here before... I feel everyone deserves [puppies!](http://images6.fanpop.com/image/photos/36300000/German-Shepherds-image-german-shepherds-36311386-1997-1636.jpg)
edit 4: This comment went gold! thank you anonymous redditor!
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t3_60s6ct
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"content": "ELI5: How come all those atomic bomb tests were conducted during 60s in deserts in Nevada without any serious consequences to environment and humans?",
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] |
The simple answer is there were serious consequences to both the environment and human health. There were marked increases in cancer rates noted, not just in Nevada, but across the midwest. Test site workers and downwinders (communities down wind from the test site) sued the federal government. To date more than half a billion dollars in compensation has been paid out.
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t3_i6gt8j
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"content": "ELI5: NASA Engineers just communicated with Voyager 1 which is 21 BILLION kilometers away (and out of our solar system) and it communicated back. How is this possible?\n\nSeriously.... wouldn't this take an enormous amount of power? Half the time I can't get a decent cell phone signal and these guys are communicating on an Interstellar level. How is this done?",
"role": "system"
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>I can't get a decent cell phone signal and these guys are communicating on an Interstellar level.
[...quoted text...]
Mobile phones work off UHF (Ultra High Frequency), so the range is very short. There are usually signal repeaters across a country, so it gives the impression mobiles work everywhere.
>wouldn't this take an enormous amount of power
[...quoted text...]
So, not really, as long as there is *nothing* between Voyager and the receiving antenna (usually very large). As long as the signal is stronger than the cosmic background, you'll pick it up if the antenna is sensitive enough.
So the ELI5 version of this would be :
- Listening to a mouse in a crowded street.
Versus
- In an empty and noise-less room, you are staring at the mouse's direction, , holding your breath, and listening for it.
EDIT: did not expect this to get so up voted. So, a lot of people have mentioned attenuation (signal degradation) as well as background cosmic waves.
The waves would very much weaken, but it can travel a long wave before its degrades to a unreadable state. Voyager being able to recieve a signal so far out is proof that's its possible. Im sure someone who has a background in radiowaves will come along and explain (I'm only a small-time pilot, so my knowledge of waves is limited to terrestrial navigation).
As to cosmic background radiation, credit to lazydog at the bottom of the page, I'll repost his comment
>Basically, it's like this: we take two giant receiver antennas. We point one directly at Voyager, and one just a fraction of a degree off. Both receivers get all of the noise from that area of the sky, but only the first gets Voyager's signal as well. If you subtract the noise signal from the noise + Voyager signal, what you've got left is just the Voyager signal. This methodology is combined with a lot of fancy error correction coding to eliminate reception errors, and the net effect is the pinnacle of communications technology: the ability to communicate with a tiny craft billions of miles away.
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t3_7h2rfn
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"content": "ELI5: Why do \"bad smells\" like smoke and rotting food linger longer and are harder to neutralize than \"good smells\" like flowers or perfume?",
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] |
They dont really; but you're keyed to be more sensitive to rotting food scents and other bad smells. Theres usually a survival reason behind it, and over time we developed a sensitivity to those scents.
Smoke is an exception; that actually does have more particles in the air that can stick to things and smell longer as a result
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r/explainlikeimfive
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t3_hth74o
|
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"content": "ELI5: What did Edward Snowden actually reveal abot the U.S Government?\n\nI just keep hearing \"they have all your data\" and I don't know what that's supposed to mean.\n\n\n\nEdit: thanks to everyone whos contributed, although I still remain confused and in disbelief over some of the things in the comments, I feel like I have a better grasp on everything and I hope some more people were able to learn from this post as well.",
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In a nutshell he revealed data that showed that the US government, and multiple allied governments had the ability to do things like listen to everyone's phone calls, read their texts, their emails, follow their internet searches, track their locations (via GPS in phones) and also remotely activate people's cell phone cameras and microphones to listen and see what people are doing in real time.
In short, it was estimated that the data revealed that the US and it's allies had transparency into roughly 80% of all digital communications in the US.
It's less that this was "Bad" honestly, more that these agencies shouldn't have been doing A. to US Citizens, and B. on US soil and C. that the major data providers, the Verizons, AT&Ts, etc, were providing the "keys" to their networks for the government to provide this access.
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t3_ue0par
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"content": "ELI5: How can nothing be faster than light when speed is only relative?\n\nYou always come across this phrase when there's something about astrophysics 'Nothing can move faster than light'. But speed is only relative. How can this be true if speed can only be experienced/measured relative to something else?",
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This is a brilliant question. It is the question the led to special relativity!
Motion is relative: the velocity of an object depends on the velocity of the thing measuring it.
Speed of light is not relative: everything measures speed of light the same.
That is the paradox. The universe tells us that is the way it is when we measure it! ...and we try to explain why. But I believe understanding should start there, not with explanations of space time.
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t3_meazfx
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"content": "ELI5: Why is W called \"double U\" when it is clearly \"double V\"?",
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When Old English was written, it used a mixture of Latin letters and older runes. One of these runes was Wynn, which was used to represent the wound that w gives today:
https://en.wikipedia.org/wiki/Wynn
That runes was sometimes replaced by the combination uu - a double u - for the same sound.
In german, the letter v changed in sound to be pronounced as f in most cases (it still is). In a few cases the v-sound was retained. To distinguish these cases, scribes began to write vv for these.
When printing was developed in what is today Germany (and to some extent Italy, but that is less relevant here), the printing press manufacturers made types for the letters that they had. Since the combination vv was very common, they made a letter for it - w. In most languages letter is called "double-v".
These printing presses and the letters for them were exported everywhere, including to England. The English quickly realized that they didn't have types for all their letters, so they made do with what they had. Since English didn't have the w before printing, they simply reused that letter for the Wynn rune, which was missing. It is called "double-u" because it was also sometimes written as "uu"
Similar story for the letter Thorn, which was also missing when printing and became the "th" combination.
https://en.wikipedia.org/wiki/Thorn_(letter)
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r/explainlikeimfive
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t3_5wvocj
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[
{
"content": "ELI5: How, at 93 million miles away, does the sun feel so warm, yet when a simple cloud passes over it the warmth is incredibly dampened?",
"role": "system"
}
] |
So when you feel the sun's warmth, you're not feeling heat coming from the sun. You're instead feeling heat created *on your skin* by the sun's light.
Light carries energy. Things with colour, like your skin, absorb light. When they do, the atoms that make them up get 'excited'. Depending on the atom, and what state its in, a few things can happen. If the atom is part of a molecule that energy can go to work breaking it out of the molecule. If the atom or molecule is on the surface of a solid or liquid, the energy can go towards flinging it off, into the air, turning into a gas.
If there's not enough energy to do either of those things, then the atom will just release the energy to its surroundings. Most of the time, most of the energy is released as heat. This is what you feel when the sun feels warm. Sometimes the energy can be released as light. This is how glow-in-the-dark things work.
A cloud doesn't block all the light from the sun, but it does ~~absorb~~ *scatter* a lot of it. *Think of water droplets in a cloud like a million tiny disco balls*. The light that gets through is either too sparce to be noticeable, or high-enough energy that it causes damage instead (ie. UV light).
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r/explainlikeimfive
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t3_bnajh3
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[
{
"content": "ELI5: Why do some animals (like spiders or lizards) spend so much time just doing nothing? What is happening and why?",
"role": "system"
}
] |
Most organisms are in a constant struggle for energy. Obtaining energy is dangerous, you have to leave your save burrow or go risk injury in a hunt.
That's why many organisms develop strategies for minimising the risks they need to take. And one of the most popular strategies is simply having simple, low demand physiologies, slow metabolisms and generally low energy needs.
Warm blooded animals are fairly unique. We're like a car with the engine constantly running. That means we're ready to go from zero to a 100 right away but we're also guzzling gas constantly, even if we're standing still. That's why warm blooded animals need toc constantly eat. Some of the smaller more high energy creatures like humming birds can starve to death in a matter of hours.
By comparison, cold blooded animals waste zero energy on body heat. The downside is that they need to warm their bodies up with external heat like sunlight in order to get their digestive enzymes working or to get their muscles ready for fast action.
But on the upside, they need so little energy that they have to take far fewer risks than warm blooded animals. Some cold blooded animals can go up to a year or even longer without food.
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r/explainlikeimfive
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t3_kecv94
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[
{
"content": "ELI5: Why do some letters have a completely different character when written in uppercase (A/a, R/r, E/e, etc), whereas others simply have a larger version of themselves (S/s, P/p, W/w, etc)?",
"role": "system"
}
] |
First of all, let's talk about the words 'uppercase' and 'lowercase'. These words come from the early history of printing, when a person called a *typesetter* would assemble each page of a book letter by letter. Each letter was a profile on a piece of lead, called a *sort*. The sorts were kept in boxes called [*typecases*](https://en.wikipedia.org/wiki/Typesetting#/media/File:Metal_movable_type.jpg), which had compartments for each letter. There would be a typecase for each *font* (also called a *fount*), which was a *typeface* at a specific size, at a specific weight (bold, medium, *etc.*), in a specific shape (upright, italic, *etc.*). A typeface is what we nowadays call a font on computers. There were actually two typecases for each font, and they were kept one on top of the other. The one on top was called the *upper case*, and contained the 'majuscule' letters; the one on the bottom was called the *lower case*, and contained the 'minuscule' letters. So the proper names for 'uppercase' and 'lowercase' are 'majuscule' and 'minuscule', respectively.
Now, on to your actual question.
Letters are just simple drawings that have phonetic meanings. (In other words, the symbols represent sounds.) The nature of the symbols is affected by the thing the symbols are written on. For example, one of the earliest writing symbols we have is [cuneiform](https://en.wikipedia.org/wiki/Cuneiform#/media/File:Early_writing_tablet_recording_the_allocation_of_beer.jpg), which was written by making marks with a stylus in a piece of clay. The shape of cuneiform marks is strongly determined by the shape of the stylus.
This is important, because the majuscules and minuscules were originally two forms of the Latin alphabet that were used for writing on different materials, and the same thing applies to the Greek alphabet.
Majuscule letters were originally *inscriptional*, which means they were carved into stone. The Roman emperor Trajan had his military victories depicted on a carved stone column called [Trajan's column](https://en.wikipedia.org/wiki/Trajan%27s_Column); at the base of this column is some writing, in the style of [Roman square capitals](https://en.wikipedia.org/wiki/Roman_square_capitals): this style is common on Roman monuments, but Trajan's column is one of the best known examples. These letters were designed by a scribe painting them on to the stone with a brush; a stonemason would then carve out the painted areas. The motion of the brush created little flairs at the beginning at end of each brush stroke; these flairs are now known as *serifs*.
However, Romans writing out documents would use [Roman cursive](https://en.wikipedia.org/wiki/Roman_cursive). Roman cursive, like all cursive writing forms, is basically a bunch of shortcuts in writing the 'proper' letters.
After the fall of the Western Roman Empire, Roman culture continued to hold considerable sway amongst the barbarians. The same writing styles were preserved, until the Carolingian Renaissance under Charlemagne (Charles the Great) in the Frankish Empire (now France) in the 800s. Charlemagne was a great believer in literacy, and despite never learning to read himself, ordered the creation of a single style of handwriting to be used across his empire, to prevent documents from being misinterpreted. The end result was a pairing of these two writing styles into the majuscule and minuscule letters of a unified alphabet. The minuscule letters, being easier to write quickly, were use normally, but the majuscule letters, with their grand and elegant forms, were used for proper nouns and emphasis. Over the succeeding thousand years, different nations would slowly adapt these letter forms and the relationships between them to their needs: the Italians developed the [Humanist minuscule](https://en.wikipedia.org/wiki/Humanist_minuscule), which later became the italic script; the Germanic peoples developed the [blackletter](https://en.wikipedia.org/wiki/Blackletter) scripts; the Irish developed the [insular script](https://en.wikipedia.org/wiki/Insular_script). This development continues today, with hundreds of typefaces released each year by type designers.
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t3_99bprm
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[
{
"content": "ELI5: Why does hearing yourself speak with a few seconds of delay, completely crash your brain?",
"role": "system"
}
] |
We subconsciously use our own voices to make sure our mouth is making the noises we want it to. The brain can’t figure out what’s wrong but still tries to correct itself
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r/explainlikeimfive
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t3_mhqeim
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[
{
"content": "ELI5: Why were ridiculously fast planes like the SR-71 built, and why hasn't it speed record been broken for 50 years?",
"role": "system"
}
] |
Before we could use satellites to take pictures from space, if we wanted to see what was going on in enemy territory, we had to take pictures from a plane.
Enemies didn't want us taking pictures so they would try to stop the plane - usually by blowing it up with missiles.
We didn't have "stealth" technology yet to keep from being seen, so if we wanted to avoid getting hit with missiles, we needed a way to avoid them. The best way we could come up with was to go so fast they couldn't catch up.
Being really high in the air helped this, because it's easier to go fast up high, and because it would take missiles so long to get up to you, you could be out of the area before they reached that height.
As a result, the SR-71 was designed to go as high and as fast as possible.
Since then, we learned to build space satellites to take our pictures, which can't be hit with missiles. We also developed "stealth" technology for planes, which keeps them from being seen on radar. This means we no longer need to develop planes for high and fast work, so the SR-71 remains the best at that.
(Edited to remove error related to a missile strike)
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r/explainlikeimfive
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t3_ircby5
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[
{
"content": "Eli5: Caffeine has almost no calories, but seems to give us a burst of energy on its own. Where does the body get this energy from? Is caffeine forcing the body to use stored fat?",
"role": "system"
}
] |
Caffeine works in two ways to make you feel that way.
First it prevents the brain from telling you that you are tired. You can think of your brain as a bunch of locked boxes with different things inside of them. Some of these boxes have things that make you happy, others make you sad. Some have things that tell you it is time to go to sleep. Caffeine jams itself into the lock on the sleepy time box so that your brain can't open it. That keeps you from feeling tired.
Caffeine also can help open the box that tells your body to go into extra energy mode. Things like your heart can work faster or slower depending on what you need. If you are sitting on the couch watching TV it's going to go slower, if you are outside working it's going to speed up. Caffeine tricks the body into thinking it needs to go into extra energy mode. Caffine doesn't create this energy, the body is just using what it has stored more quickly. Not really any different from you step on the gas in a car. You are telling it to burn more fuel and go faster.
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r/explainlikeimfive
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t3_9durlp
|
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[
{
"content": "ELI5: Why does your body feel physically ill after experiencing emotional trauma?",
"role": "system"
}
] |
The limbic system is responsible for this feeling! The limbic system is the emotion and memory part of your brain, and is hugely important for how you experience and perceive things. The limbic system has a direct impact on the autonomic nervous system. If you perceive that you're in a calm situation, your limbic system will impact the rest of your brain, and thus the rest of your body, to make your body act as if it's in a calm situation. The hypothalamus is also part of the limbic system and plays a role in your body maintaining chemical balances. It is also a reason why you feel physically ill.
To give a little bit more detail on a few things:
The sympathetic portion of the autonomic nervous system is the the part of your body that makes your heart beat faster, makes you breathe faster, makes your pupils dilate, makes you sweat, and makes you stop digesting food (your blood is diverted to your muscles so you can run if needed). It is the fight of flight response in your body and has a cascade effect on the rest of your body. If your limbic system is going crazy with emotional trauma, it'll make your sympathetic nervous system ramp up as well. If you just ate and your body all of the sudden stops digesting food, you may throw up.
The limbic system (emotion and memory area of the brain) also directly impacts almost every other part of your brain. The limbic system is smack dab in the center of your brain, thus connects to everything. This is why being in a really intense situation can change how you feel physically and how you even perceive (time slowing down) a situation. One of the important parts of the limbic system is the hypothalamus.
The hypothalamus plays a huge role in maintaining your body's "natural state". If you need food, your hypothalamus is the part that makes you feel hungry. The hypothalamus is part of the limbic system, so it is under these same controls of emotion. Under a really stressful situation, your hypothalamus will react with the release of cortisol, which will affect your blood sugar and can make you feel sick.
Now, all of this kind of paints the limbic system as the bad guy, but that's not really true. The limbic system is also what integrates emotion into what we experience when something is positive. It's why your mom's cooking tastes better if you have fond memories of her. It's what makes your heart flutter when you're in love. It's what makes you remember things. Heck, it is even the reason why a truck horn can go off in the dead of night and you won't wake up, but when someone whispers your name you will.
Edit: /u/dr_bewbz goes into the same thing in her response but with more focus on the autonomic nervous system. It is very accurate and a great response.
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r/explainlikeimfive
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t3_6y9qw9
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