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Wednesday, November 21, 2018

Does Large Hadron Collider need re-calibration after redefinition of SI units?

Does Large Hadron Collider need re-calibration after redefinition of SI units?


Does Large Hadron Collider need re-calibration after redefinition of SI units?

Posted: 20 Nov 2018 12:53 PM PST

How are measurements in different detectors over at LHC connected to the current values of speed of light, kilogram, etc? Would redefinition of SI units need updates in other kinds of measuring devices in science laboratories across the world?

submitted by /u/andrybak
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AskScience AMA Series: I'm Dr Melanie Windridge, a plasma physicist who combines science with adventure. I have summited Mount Everest to explore the science that gets us to the top and I've written a book about the northern lights. AMA!

Posted: 21 Nov 2018 03:14 AM PST

I'm Dr Melanie Windridge, a plasma physicist who combines science with adventure. In Spring 2018 I climbed Mount Everest and explored the science that helps climbers survive at high altitude and under extreme conditions.

Along the way I spoke to experts and created a video series called "The Science of the Summit". It's hosted on the Institute of Physics' YouTube channel and covers statistics, fitness and training, risk and motivation, oxygen systems, mountain weather, the chemistry of clothing, communications in remote locations, physiology and medicine, and helicopter rescue.

An improved understanding of high-altitude physiology, acclimatisation and nutrition was instrumental in the British success on Everest in 1953. Edmund Hillary and Tenzing Norgay were the first people ever to stand on the top of Everest. They were supported not only by their expedition climbing team mates but also by the work of physiologist Griffith Pugh and others. Since their successful summit, science, technology and our understanding of physiology at high altitude have further improved.

In 2016 I published "Aurora: In Search of the Northern Lights". The book is a journey of discovery and explores the visual beauty, legends and science of the northern lights, including the developing threat of space weather. I'm fascinated by the aurora. It's a marvel unlike any other in which the powers of astronomy, geology, magnetism and atomic physics combine to create one of the wonders of the natural world.

My explorations of the aurora have led me to many Arctic destinations such as Sweden, Norway, Canada, Iceland and Svalbard.

I have written a blog about Science at the Extremes for several years. You can have a look and subscribe to it here: http://melaniewindridge.co.uk/blog_home

I'm here to talk about science and adventure - my experiences on Everest and in the Arctic with the aurora, and the science and technology that support high-altitude climbers and how they have improved and developed over the years. I'll start around 4pm UT (11am ET). AMA!

submitted by /u/AskScienceModerator
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Why does the edge of the Oort cloud continue to revolve around the sun when its closer to Proxima Centauri? Why is the edge of the Oort cloud still considered part of the solar system?

Posted: 20 Nov 2018 11:46 PM PST

From my understanding, the Oort cloud is like a sphere that revolves around the earth at a distance of up to 200,000 AU from the solar system. It is the edge of the solar system. Meanwhile, the closest star; Proxima Centauri is just 267,000 AU away. Why is the edge of the Oort cloud still considered part of our solar system when it is far closer to Proxima Centauri, and is the very edge of the Oort cloud still a sphere-like shape as is theorised? If so, why when it is closer to Proxima is it still considered a section of our solar system?

Edit: Rephrasing

submitted by /u/uriharibo
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Is there an altitude on Venus where both temperature and air pressure are habitable for humans, and you could stand in open air with just an oxygen mask?

Posted: 21 Nov 2018 07:42 AM PST

I keep hearing this suggestion, but it seems unlikely given the insane surface temp, sulfuric acid rain, etc.

submitted by /u/Nerrolken
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If the Moon was orbiting the Sun instead of the Earth, would it be classified as a planet or a dwarf planet ?

Posted: 21 Nov 2018 07:25 AM PST

How did early scientists recognise a new element?

Posted: 21 Nov 2018 02:23 AM PST

For example, I read that Scheele and Priestly discovered oxygen independently in 1772 and 1774 respectively, but it was Lavoisier, who (again independently) discovered it in 1775, that first recognised it as an element. What did Lavoisier see that the other two hadn't?

submitted by /u/iwzhzbb
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Are how dinosaurs sound in movies based on scientific data or just how cool it sounds?

Posted: 20 Nov 2018 09:24 PM PST

What determines life expectancy in a lifeform?

Posted: 21 Nov 2018 05:08 AM PST

Yesterday I visited my neighbor and he introduced me to his parrot. a smart grey fella with a red chest. my neighbor then told me he was 77 years old. I thought it was freaky that this bird has lived this long and I started googling average life expectancies of animals, and they seem ... completely random?! So I wanted to ask, is there any science behind why some animals live longer and some don't and could you explain?

submitted by /u/evilwalrusses
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Is there any formula that can be used to calculate what temperature a white dwarf of a given mass will be in x years?

Posted: 21 Nov 2018 04:28 AM PST

I have Googled around and only found incomplete ones that cannot really be used to calculate it. Thanks in advance to people for answers, not a homework question, I just have an unhealthy fascination with far future of the universe. I know that white dwarfs take 1015 years to cool to 5 K and possibly much longer than that as WIMP annihilation may heat them to 63 K (according to this often quoted, and good paper https://arxiv.org/abs/astro-ph/9701131 ) and that the oldest white dwarfs in our universe are 11-12 Gyr old and are at 3900 K, but I haven't been able to find any info about how fast it cools in the meantime. It seems that it cools very fast (in deep time terms) from the 100000 K temperature of a pre-white dwarf (planetary nebula's central star) to 25000 K of a "young" white dwarf like Sirius B (330 Myr old) then much more slowly to around 6200 K (Van Maanen's star, 3.13 billion years old) and MUCH slower than that to 3900 K (like WD 0346+246, which is almost 9 billion years older, but still has more than half of Van Maanen's star temperature).

submitted by /u/RAMDRIVEsys
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Ask Anything Wednesday - Engineering, Mathematics, Computer Science

Posted: 21 Nov 2018 07:11 AM PST

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Engineering, Mathematics, Computer Science

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions.

The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here.

Ask away!

submitted by /u/AutoModerator
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Is strong narcissm necessarily a malignant/negative personality trait?

Posted: 21 Nov 2018 06:49 AM PST

Is there a relation between enthalpy of neutralization and the pH of acid if the alkali used for reaction is the same?

Posted: 21 Nov 2018 06:47 AM PST

I know that the temperature, mass and specific heat capacity affect the enthalpy but is there anything that would explain why different acids reacting with the same alkali would make a difference?

submitted by /u/13R0
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Does the expansion of the universe equate into trajectories of space craft to make sure they hit their target ?

Posted: 20 Nov 2018 06:38 PM PST

Is Romain lettuce more susceptible to E. coli than other types of vegetation? If so, why?

Posted: 20 Nov 2018 06:27 PM PST

If the Sun would suddenly disappear, would it take us minutes to realize the gravity is gone?

Posted: 21 Nov 2018 05:18 AM PST

Me and one of my colleagues (both absolute laymen) were discussing this just now. He argued that there is not gravity particle in the Standard Model and therefore gravity is not an 'interaction'. his conclusion was that this means that if the Sun would suddenly disappear the change in gravity would be literally instant, disregarding the speed of light.

I personally do not believe this, since the speed of light as a cosmic speed limit has been ingrained into my mind by popular science programs. Can someone here please explain me how this would work theoretically?

submitted by /u/Arkafold
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How much lower were water levels during the time of Polynesia expansion ?

Posted: 21 Nov 2018 05:15 AM PST

Why do we want to care about Hilbert spaces beyond our own three dimensions?

Posted: 20 Nov 2018 07:43 PM PST

Practically speaking, I'm unable to see what uses we may have for solving extra-dimensional problems beyond our own three dimensional Euclidean space; That is to say, I fail to see any practical use or application of trying to understand what exists outside our plane of existance. Can anyone help explain to me why we created Hilbert space to begin with, and what we can do with them?

submitted by /u/_Sunny--
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Is the sun at the same focus for all elliptical orbits?

Posted: 20 Nov 2018 11:18 PM PST

Since there are two focii for any ellipse and the sun is at one focus of an elliptical orbit, is it the same one for all planets?

submitted by /u/sirDeanofShire
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Why is there no standardized way of measuring speaker-system audio quality? What makes it difficult to objectively assess?

Posted: 20 Nov 2018 03:19 PM PST

Sure, there's a big subjectivity factor. But I would have thought there would be a way to holistically (or otherwise) quantify clarity, fidelity, warmth, space, and all the other things audiophiles seem able to discern, but technology apparently can't.

submitted by /u/AnotherThroneAway
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Why does the sun set at a different time every evening?

Posted: 20 Nov 2018 06:12 PM PST

Why does the sun set at a slightly different time each evening? I thought the Earth rotated at the same speed constantly?

submitted by /u/OigaShaboiga101
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Is there a standardized naming convention for stars and exoplanets?

Posted: 20 Nov 2018 01:22 PM PST

Tuesday, November 20, 2018

Why is consuming activated charcoal harmless (and, in fact, encouraged for certain digestive issues), yet eating burnt (blackened) food is obviously bad-tasting and discouraged as harmful to one's health?

Why is consuming activated charcoal harmless (and, in fact, encouraged for certain digestive issues), yet eating burnt (blackened) food is obviously bad-tasting and discouraged as harmful to one's health?


Why is consuming activated charcoal harmless (and, in fact, encouraged for certain digestive issues), yet eating burnt (blackened) food is obviously bad-tasting and discouraged as harmful to one's health?

Posted: 19 Nov 2018 12:46 PM PST

Do snakes preferentially bend to the left or to the right when forming loops?

Posted: 19 Nov 2018 09:14 PM PST

How did chemists explain reactions before the discovery of the atom?

Posted: 19 Nov 2018 12:50 PM PST

In an SSD drive, how is the data persistent, even if the power is off?

Posted: 20 Nov 2018 03:23 AM PST

I'm a CS student and I know the ins and outs of data storage in RAM. But RAM needs electricity to save data. Since an SSD (I assume) uses the same basic technology, how is it possible that we can take it off the grid and the data is still saved?

submitted by /u/flumsi
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If we can discharge excess voltage into the Earth whenever we need to, why can't we draw a steady supply of electricity from the Earth in a similar way?

Posted: 19 Nov 2018 02:35 PM PST

What determines what wavelength of light is reflected from object?

Posted: 19 Nov 2018 09:39 PM PST

If i have a green apple, shined on by light from sun. The apple appears green. Because all wavelengths of light are absorbed except for some that appear green to us. But what determines the color of the apple? Is it the size of the molecules on the apple surface?

submitted by /u/reznik99
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Could an electron itself know both its own position and momentum?

Posted: 20 Nov 2018 01:02 AM PST

How does helium cause a MEMS oscillator to stop working?

Posted: 19 Nov 2018 03:00 PM PST

Helium has recently been identified as the culprit in killing some Apple hardware, due to interfering with MEMS oscillators: https://www.reddit.com/r/sysadmin/comments/9mk2o7/mri_disabled_every_ios_device_in_facility/

Is the oscillator small enough that individual helium atoms can jam between the moving parts? Is it some sort of chemical effect? What's actually going on?

submitted by /u/kendfrey
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How do the people on North Sentinel Island and people in other isolated tribes maintain genetic diversity?

Posted: 19 Nov 2018 05:13 PM PST

Presumably for the past 10,000 years, the people of North Sentinel Island have been procreating with around 100-1000 people. With a gene pool that small how are the islanders not suffering from genetic diseases? Is there a specific reason, or have they just been maintaining genetic diversity.

submitted by /u/Healthy-sama
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What caused the Siberian eruptions during the Permian extinction?

Posted: 19 Nov 2018 04:25 PM PST

A sea of lava the size of the US just appearing isn't normal.

submitted by /u/EmptyToad45
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Does my body need more than 7-8 hours of sleep after I stay up for 24 hours or more and why? Thank you science

Posted: 19 Nov 2018 04:28 AM PST

Just wanna know if there is a difference if I stay up for 24 hours and I sleep for 7-8 hours, compared to if I were awake for 12-18 hours and got the same amount of sleep.

submitted by /u/vibekilluh
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What does it mean that a photon has an oscillating magnetic field perpendicular to an oscillating electric field?

Posted: 19 Nov 2018 09:03 PM PST

I'm speaking particularly about the common representation of a photon as two in-phase sine waves at right angles to each other. What exactly is oscillating? A couple places said it was the magnitude of each respective field, which I think refers to the strength and length(?) of the field lines "generated" by the field. But what shape do the field lines take? Is it the kind of pattern you would see with, say, iron fillings and a bar magnet? Additionally, the fields are projected in the 3rd dimension right? How can they be rotated at 90% then? Or is it something to do with quantum numbers?

When the magnitudes of both waves reaches 0, do the fields diminish to nothing or just stop influencing anything around them? If someone put a magnet near a stream of radio wave with a noticeably long wavelength, could the exertion of forces on the magnet be detected?

Sorry I don't really understand EM waves at all and I'm probably dumb for trying to understand with a cursory knowledge of physics.

submitted by /u/TheGreatCornlord
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The Bay Area CA had an aqi ranging from 140-240+ over the past 10 days. We are expecting rain to clear this up. What sort of toxins can we expect in the water once it hits the ground?

Posted: 19 Nov 2018 04:04 PM PST

How are gas planets formed?

Posted: 19 Nov 2018 07:42 PM PST

If gas planets are just giant balls of gas than how are they formed in space and how do they gain mass and gravity?

submitted by /u/any_username_ideas
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Volcan de Fuego in Guatemala is one of the most active stratovolcanoes in the world, and sometimes has multiple small eruptions in one hour. Why was the June 3rd, 2018 eruption so powerful and devastating?

Posted: 19 Nov 2018 04:52 PM PST

Are there such things as albino variants of trees?

Posted: 19 Nov 2018 08:37 AM PST

My wife and I bought a new house over the summer. When we first moved in I noticed this "white" sapling growing in our yard. I thought it might just be a nitrogen deficiency, but I decided to let it keep growing and see what happens. The sapling has grown quite a bit, but all the new leaves are white. Here's a picture:

https://imgur.com/gallery/IIM17th

The plants around it don't seem to have any issues with white leaves and there are several more of this type of tree around that look normal. Could this be an "albino" version of this type of tree? I spend a lot of time in the woods and whatever this tree is, it's pretty common around here, but I have never seen this white leaf variety. Thanks in advance.

submitted by /u/cubanesis
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Why can we still hear the cosmic microwave background? How much longer will we be able to hear it? The big bang was almost 14 billion years ago, how can we possibly see something from that long ago given that it no longer exists?

Posted: 19 Nov 2018 06:58 PM PST

What is the rate of decay of Long-Term Potentiation (LTP)?

Posted: 19 Nov 2018 10:21 PM PST

In other words, at what rate do the synaptic connections formed during LTP decay as a result of inactivity?

The reason I'm asking is because I'd like to know how quickly we forget learned "skills".

submitted by /u/ALefty
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Does quantum superposition affect every observer individually?

Posted: 19 Nov 2018 05:45 PM PST

Schrodingers cat is an example of how a system exists in all of it's possible states until it's observed, and then it collapses into one of them.

But what if the schrodingers cat box is contained within another steel box along with the observer. When the observer opens the cats box, the wave function collapses and the observer sees one state or the other, but for another observer outside of the outer box would the state of the cat still be a superposition of the dead or alive state since he didnt observe the box?

In other words can a quantum superposition collapse for one observer but not the other?

submitted by /u/zarek911
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How does a low battery in a kid's toy affect the frequency of the audio output?

Posted: 19 Nov 2018 10:53 AM PST

I recently watched this video: https://www.youtube.com/watch?v=wMmEnbryZnA

And I was wondering how those sound clips could get distorted by a low voltage battery.

submitted by /u/ohnoitsgodzilla
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How are these kinds of layered stones formed? (Image inside)

Posted: 19 Nov 2018 08:22 AM PST

Some nine years ago, when I was still in school, I had found a strange looking stone with layered patterns. Recently looking at my old stuff, I found it again. Which makes me wonder how these kinds of layers are formed:

Photo

Edit:

Different angles

With tape for scale

The sample is about 4 centimeters long, 3 centimeters wide and about 2.5 centimeters in height.

I found it in my school playground just lying in the dust among other things, and live in India, the westernmost part.

The color of the rock is actually yellowish to yellow-orange and slightly brown in some places.

With Magnifying glass

submitted by /u/Gayoka
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Monday, November 19, 2018

How do obscure/rare sea creatures locate each other to breed?

How do obscure/rare sea creatures locate each other to breed?


How do obscure/rare sea creatures locate each other to breed?

Posted: 18 Nov 2018 07:20 PM PST

does flying through clouds have any effect on the speed of an aircraft?

Posted: 18 Nov 2018 07:52 PM PST

Title pretty much says it all.

Is there any effect on the speed of an aircraft? Clouds do have mass correct?

submitted by /u/ConstantBad
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What effect would anti- depressants have on someone who is not depressed?

Posted: 18 Nov 2018 11:33 AM PST

What is the critical mass of gas required for it to stick together in deep space due to gravity and not disperse due to diffusion?

Posted: 19 Nov 2018 04:58 AM PST

I just found out that while mars has about 1/10th the mass of earth it has 38% of the gravity. This suggests a non-linear relationship between mass and gravity at the surface. What causes this effect? [Physics]

Posted: 19 Nov 2018 03:03 AM PST

Follow up question: Does this effect mean that the gravity on the surface of planets that are significantly larger than earth would be survivable for humans?

submitted by /u/Uncleniles
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Why is it when you "haaaa" hot air comes out but when you "huuuuu" cooler air comes out?

Posted: 18 Nov 2018 08:52 PM PST

Does the air come out of different places in my body? If so where does the different air come from?

submitted by /u/theleeforce
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What's the mechanism allowing our eyes to move in the same direction?

Posted: 18 Nov 2018 11:54 AM PST

What happens to the vacuum energy next to mass agglomerations?

Posted: 19 Nov 2018 04:38 AM PST

  1. If gravity changes the space curvature, does that mean anything for the vacuum energy next to big masses like galaxies or black holes?
  2. Does space gets more "compressed" if it gets curved?

  3. Will the vacuum energy be higher per space-unit if space is "compressed" or doesn´t it change at all?

  4. How much vacuum energy is there? Wiki doesn´t know.

Thanks!

submitted by /u/bnbgrs
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Objects that reflect only non-visible wavelengths?

Posted: 19 Nov 2018 12:31 AM PST

I had a few questions pop into my head last night. Hypothetically let's say there is a material that only reflects wavelengths of non visible light, such as ultra violet or infra red, or maybe they only reflect radiation like microwaves or x-rays. What would those materials look like to the human eye? Would they be completely black if they only reflect non-visible light? Do any of those materials exist? Are there any practical purposes for those kinda of materials. The sooner I get an answer the sooner I can sleep easily.

submitted by /u/Thatonedinoguy
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What makes Ciliac Disease so hard to cure?

Posted: 18 Nov 2018 06:55 PM PST

I happen to have it, though I have done little research into it. I ask this for three reasons:

New daughter (biological), is this a genetic concern? (I was adopted, no genetic history)

Serving in the Army, sometimes tough cookies, literally. Will I become incapable of working at peak performance due to this?

What other factors does this put me or my lineage at risk for?

-Thankful Father and Soldier.

submitted by /u/Synaptic_Productions
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Substrates Reactions Growth of Graphene?

Posted: 19 Nov 2018 12:53 AM PST

Hi,

Can anyone tell me what is the type of substrate used (elements it is made up of)? It appears to be a solid. What is the reaction of the layer of graphene particles on the copper surface that are from the reaction of the gases after it is broken down? Is there a reaction between the graphene particles and the substrate? If there is, what is the reaction that occurs? Does the layer of graphine react with a chemical which forms a graphene solid (the layer is solidified in the chemical).

If someone could please help, thank you.

Zackhie

This video shows the image (diagram) of the reaction

https://www.youtube.com/watch?v=h6oUgIvBR8E

submitted by /u/Zackhie
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Is time exactly symmetrical? If we were to rewind it would it play back as the reverse of it playing forwards?

Posted: 19 Nov 2018 12:38 AM PST

Is this true always?

submitted by /u/nicholasweber
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Does the body burn more calories in hot or cold temperatures (at rest)?

Posted: 18 Nov 2018 09:46 PM PST

How and why does lactose intolerance suddenly happen in adults?

Posted: 18 Nov 2018 09:57 AM PST

How does blood "know" where to clot?

Posted: 19 Nov 2018 02:09 AM PST

Like, how does it "know" it needs to clot as soon as a wound is bleedind?

submitted by /u/mobilereign
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Will Mount Everest always be the tallest mountain?

Posted: 18 Nov 2018 01:42 PM PST

The sunset in Barrow, AK for the final time for 66 days, is there somewhere else in the world that the sun won’t go down for that long?

Posted: 18 Nov 2018 08:53 PM PST

Pretty much the title. If the sun is setting in Utqiaġvik (Barrow) until January is there an opposite event happening elsewhere?

submitted by /u/yelpats
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What happens to electron orbitals in plasma?

Posted: 18 Nov 2018 04:53 PM PST

My understanding of plasma is a gas that has free flowing/ non localized electrons. Does this mean that their are no orbitals for matter in this state or are only the valence electrons free flowing?

submitted by /u/juuzo
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Why is it that some metals or minerals are shaped like cubes or have relatively perfect edges?

Posted: 18 Nov 2018 06:38 PM PST

Do large reptiles like gators have to “Roost” on their eggs the way birds do?

Posted: 18 Nov 2018 03:06 PM PST

Does fog absorb or reflect light?

Posted: 18 Nov 2018 08:58 PM PST

I've always wondered this. When there's snow on the ground, my small town is illuminated during a foggy night. Is the light from town being absorbed by the fog, making it seem brighter? Also relevant to driving at night; during intense fog I can't see lights that are a mile or more away. What is happening?

submitted by /u/cassieroseb
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How did allergies (specifically anaphylaxis) evolve in humans? I just don’t get how closing off the airway in response to a “pathogen” helps at all.

Posted: 18 Nov 2018 12:05 PM PST

What’s the current status of Zika? The news hasn’t been reporting it as threatening as it was before- is this because the news is bored of it and it is just as bad as it was a year or ya ago or is it actually subsiding? Do we have a vaccine available?

Posted: 18 Nov 2018 08:39 PM PST