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Thursday, July 11, 2019

How is it known that everyone with blue eyes has one single ancestor, rather than this mutation occurring in multiple individuals at many different times?

How is it known that everyone with blue eyes has one single ancestor, rather than this mutation occurring in multiple individuals at many different times?


How is it known that everyone with blue eyes has one single ancestor, rather than this mutation occurring in multiple individuals at many different times?

Posted: 10 Jul 2019 11:45 PM PDT

AskScience AMA Series: I am Dr. Matt McCarthy, a staff physician at NewYork-Presbyterian Hospital, and I hunt superbugs for a living. In my new book, Superbugs, I give a behind-the-scenes look at the search for new cures for these deadly microbes. AMA!

Posted: 11 Jul 2019 04:00 AM PDT

Hi, Reddit! I am Dr. Matt McCarthy, staff physician at NewYork-Presbyterian Hospital and assistant professor of medicine at Weill Cornell, where I also serve on the ethics committee. In my new book, Superbugs, I take readers behind the scenes of a clinical trial involving a new treatment for lethal, drug-resistant microbes. I also share the history of antibiotics and the ethical debates involved in cutting-edge medicine, as well as the stories of the patients we treated with the drug during the trial.

Superbugs are everywhere (check out my recent op-ed). If you have questions about my research, superbugs, medical ethics, or generally working in a hospital, I am here for it! Here's my proof, see you at 12pm ET (16 UT), AMA!

submitted by /u/AskScienceModerator
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Why does a dead battery work for a second when I remove it and put it back in the remote?

Posted: 11 Jul 2019 01:09 AM PDT

On HBO’s Chernobyl, a pregnant woman is exposed to radiation by contact with her irradiated husband. When she gives birth the baby dies. It’s said the baby absorbed all the radiation from and the mother was saved because of this. What mechanism is this caused by? Is it potentially true?

Posted: 10 Jul 2019 09:56 PM PDT

Are ant scent trails directional? When ants follow a scent trail to a food source and back to their colony, how do they avoid getting turned around and going the wrong direction?

Posted: 11 Jul 2019 06:46 AM PDT

Also, what cleaning product can I use to remove that trail so the damn things stop coming into my kitchen?

submitted by /u/GreenStrong
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Iodine tablets not necessary for aged 40+ after a nuclear accident?

Posted: 11 Jul 2019 05:33 AM PDT

People below age 40 should take iodine supplements in the event of a nuclear accident. To block iodine 131 absorption in the thyroid. Yet older people shouldn't do it, because they have a lower chance of developing cancer in the thyroid and have an increased risk of negative side effects.

The wiki page for this type of cancer says it most commonly occurs between the age 35 and 65. How is this not a contradiction? Doesn't this mean they have an even higher chance?

submitted by /u/UglySalvatore
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Is the dilution of any acid exothermic?

Posted: 11 Jul 2019 04:17 AM PDT

From what I know, the dilution of sulfuric acid is exothermic due to the ionoziation of the acid,

H2SO4 -> H+ + HSO4-

HSO4- -> H+ + SO42-

where the equation

H+ + H2O -> H3O+

...is highly exothermic. Does this apply to all other acids? For example, In the dilution of hydochloric acid, the acid ionizes like so:

HCl -> H+ + Cl-

H+ then reacts with water, so would the dilution of any acid be exothermic? If so, would they all be exothermic to the same degree i.e. same amount of energy released per mole of H+ ions?

submitted by /u/NathanTew
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What will happen if a coastal city floods while the water is full of toxic algae?

Posted: 10 Jul 2019 11:34 AM PDT

Right now Barry is on track to become a hurricane and hit New Orleans. There is also a large toxic algal bloom in the Gulf Coast which has shut down all the beaches in Mississippi and a dozen beaches in Louisiana. Additionally, a toxic algal bloom has been seen in Lake Pontchartrain. What happens if Barry hits New Orleans and the city floods with this water? Does it create additional hazards and if so how do public health and emergency services recommend citizens respond? Relatedly, with all of this rain should we expect these agal blooms to grow? Or do huge storms like hurricanes disrupt this?

submitted by /u/firedrops
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How does an Oasis city in deep arid desert keep its waterbody from becoming a salt lake? And how do acient people live around oasis prevent waterbody contamination from thousands years of agriculture and sewage?

Posted: 11 Jul 2019 12:45 AM PDT

Is the identity of dark matter completely unknown, or is it likely known, and we're just waiting for proof and scientific consensus?

Posted: 10 Jul 2019 10:25 PM PDT

For example, if dark matter is bread, then it's not completely unknown (but still surprising), and we're just waiting for someone to prove it.

submitted by /u/badon_
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Are there seasons in other planets?

Posted: 11 Jul 2019 12:59 AM PDT

I just binge watched Evangelion. The ed (Fly Me to the Moon by Frank Sinatra) had the lyrics "let me see what spring is like on a, Jupiter and Mars"

Just a really stupid question from a 17 year old

submitted by /u/TheoTheOreo
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How did astronomers figure out the shape of the Milky Way?

Posted: 11 Jul 2019 05:57 AM PDT

Are we being duped into buying beauty products?

Posted: 10 Jul 2019 11:42 PM PDT

Is it truly nonsensical to apply treatments to your skin and hair? Am I really wasting money on vitamin e oil, and other beauty and health products? I was told today that the body doesn't absorb from the outside, rather only from within. I was all on board believing that, but now I'm thinking about all the Epsom soaks I take and keratin hair treatments... what's the dealio?

submitted by /u/smushyu
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Does the movement of galaxies and other objects in outer space affect the way photos of galaxies that are light years away from earth are taken? And is the reason that this pictures take a long time to complete?

Posted: 11 Jul 2019 02:10 AM PDT

What is Loop Quantum Gravity?

Posted: 11 Jul 2019 04:34 AM PDT

Can you please answer this questions:

  • What is LQG?
  • What advantages and disadvantages does it have?
  • Why is it String Theory's main rival?
submitted by /u/hiimjohn04
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How much extra visible light does the ozone hole let in?

Posted: 11 Jul 2019 04:34 AM PDT

Would the ozone hole let in more light on the violet side, and cause a visible change in natural lighting?

submitted by /u/ghostcaesar
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Do goosebumps appear in the same location every time?

Posted: 11 Jul 2019 04:02 AM PDT

Say you are cold and have goosebumps on your arms. The next time you get goosebumps on your arms will the individual 'bumps' be in exactly the same place?

submitted by /u/frankthemantis
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What is "nothing" made of?

Posted: 10 Jul 2019 09:31 PM PDT

So if I had a vaccuum chamber and pumped all of the air out (which would be o2 n2 h2 etc) to an absolute vacuum, then the chamber should then be free of any molecules.

Is there anything in the now created void/ making up the space?

Which brought me to space.. so that's a vaccum, and uv rays, light photons, solar radiation etc. travel from the sun.. but is there no real medium they travel through?

Just thinking, and I couldnt come up with an answer based off my knowledge lol

Thanks!

submitted by /u/Rankinstein1992
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How do mosquitoes know what is living and what is not living (so they can enjoy [high quality all natural] blood), even in the dark?

Posted: 10 Jul 2019 09:07 PM PDT

With home breaker boxes, why do they not provide any form of a reading prior to 'blowing'?

Posted: 10 Jul 2019 11:14 PM PDT

We constantly pop a breaker that's rated for 15A/110V as it's shared between three rooms. The box was replaced in full about two years ago, breakers and all, but it basically looks the same as the previous 20+ years.

A quick Google search doesn't seem to show anything on the market that could provide an 'active load' reading and with the technology being available, it's a bit surprising that households seem to be lagging behind. At work I see it on PDUs in datacenters, and most are rated for much higher current overall (commonly 15A per phase, three phase), so why isn't this more common in standard homes that may be pulling far less power?

Is it even possible to incorporate in such a small box/breaker or is it more of a safety concern?

submitted by /u/Antics253
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What happens to an atom whose electrons have ascended to a higher orbit due to light absorption, after said light is switched off?

Posted: 10 Jul 2019 10:46 PM PDT

So I was just reading that the reason objects appear different colours to us, is because the molecular makeup of the material the object is made from will cause certain wavelengths of light to be absorbed, and others to be reflected

This happens because the electrons surrounding the atoms/molecules can use the energy from the light to "jump" to a higher orbit, but only if the energy of the photon of light that hits it perfectly matches the amount of energy needed to make the jump. This leads to only specific wavelengths being absorbed by the material. Wavelengths of light that don't correspond with the energy difference needed for an electron to ascend to a higher orbit are reflected, this giving an object its colour.

My question after all that is: what happens to all those electrons that are now in a higher orbit once the light is turned off? Do they jump back down to their ground state? And if so, how is the energy released to allow this? Light? Wouldn't that cause everything to glow after the lights are turned out? Or cause everything to look white as electrons jumping between orbits would be absorbing and releasing the same wavelengths of light, cancelling each other out?

And what about the atoms whose electrons have already ascended to a higher energy orbit but are still being bombarded by photons? Can the electrons keep achieving higher and higher energy states?

Obviously I'm very confused, any help would be much appreciated 😅

submitted by /u/wild___turkey
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Oftentimes we hear "He/she's a fighter" when someone is critically injured or unwell, but still hanging in. How much does willpower of that individual actually matter at such a time?

Posted: 10 Jul 2019 12:34 PM PDT

If a person internally were to think about giving up, do the bodily functions like the immune system or the repair and recovery systems also, in a sense, stop working as hard?

submitted by /u/APBhurke
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Wednesday, July 10, 2019

How much methane is likely to be released by the melting of permafrost due to Global Warming, and what are the likely impacts of this (how bad will the effects be)?

How much methane is likely to be released by the melting of permafrost due to Global Warming, and what are the likely impacts of this (how bad will the effects be)?


How much methane is likely to be released by the melting of permafrost due to Global Warming, and what are the likely impacts of this (how bad will the effects be)?

Posted: 09 Jul 2019 05:12 PM PDT

Will the rings of Saturn eventually become a moon?

Posted: 10 Jul 2019 06:22 AM PDT

As best I understand it, the current theory of how Earth's moon formed involves a Mars sized body colliding with Earth, putting a ring of debris into orbit, but eventually these fragments coalesced to form the moon as we see it now. Will something similar happen to Saturn's rings? How long will it take.

submitted by /u/dezstern
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Any hope for commercial nuclear fusion of heavier elements?

Posted: 10 Jul 2019 06:27 AM PDT

So most efforts are focused on hydrogen fusion (deuterium+tritium) if I understand correctly.

What makes us not even consider Carbon+Carbon fusion for example? Is there any chance we might better control that process ?

submitted by /u/Me_ADC_Me_SMASH
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How, exactly, does dissipating the proton gradient across the inner mitochondrial membrane (e.g. during brown adipose tissue thermogenesis) produce heat?

Posted: 10 Jul 2019 02:44 AM PDT

It is well known that cells of brown adipose tissue, used for thermogenesis, express uncoupling proteins which dissipate the proton gradient across the inner mitochondrial membrane, generating heat. There are also medications (2,4-dinitrophenol) that do the same thing, leading to higher energy usage but uncontrolled heat production.

However, in explanations of this phenomenon, the exact explanation of how this photon transport leads to heat generation is always handwaved away as something like "the energy of the proton gradient is wasted as heat" in more or less complex formulations. I am interested in the exact physical mechanism which links the proton influx into the mitochondrial matrix to an increase in temperature, which I have never been able to find explained anywhere.

Also, a further question which may or may not be answered by my primary question: why does dissipation of a concentration gradient not lead to heat generation in other scenarios (e.g. when concentration gradients across neuronal cell membranes are dissipated at the postsynapse or the axon, during signal transmission; or during a large scale calcium influx into muscle cells)?

submitted by /u/meew0
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What specifically tells scientists where a meteorite formed in the solar system?

Posted: 10 Jul 2019 05:49 AM PDT

Saw a piece on Atlas Obscura today that discussed the Benld meteorite. It is described as "having formed between Mars and Jupiter". Some meteorites have been traced to Mars, Vesta or just regions of the solar system. While I understand the concepts of the "Frost Line" and differentiation in the pre-solar nebula, it's not clear what specific indicators are used locate the origins of different meteorites, and what the underlying theory solar system formation those location attributes are based on --e.g. with the new models of planetary migration in the early solar system history, do the location indicators still hold up?

submitted by /u/shiningPate
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Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology

Posted: 10 Jul 2019 08:12 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Biology, Chemistry, Neuroscience, Medicine, Psychology

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!

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How do fireflies control their light?

Posted: 09 Jul 2019 05:56 PM PDT

I know how it's made, I just don't know how they control it.

submitted by /u/HiggsMechanism
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How do cameras compare to the human eye?

Posted: 09 Jul 2019 02:00 PM PDT

Will there ever be a point that cameras can achieve the same standard as the human eye, when will that be and why hast it already happened?

submitted by /u/spatialanomaly12
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What effect do Beta2 Agonists have on the retina?

Posted: 10 Jul 2019 02:17 AM PDT

Beta2 Agonists are broncodilators, what effect do they carry inside the eye? Vasodilation? Vasoconstriction? I am just curious if any brilliant people can help shed somelight on this as I cant find information on its effect on the eye.

Hard question-

submitted by /u/Mishman7
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How does Earth's magnetic field actually "block" solar and cosmic radiation on a fundamental level?

Posted: 09 Jul 2019 10:19 AM PDT

What is the nuclear anapole moment?

Posted: 09 Jul 2019 06:22 PM PDT

I was reading a little about APV a while ago to find out the current state of experimental research and see what kind of atoms are appropriate for APV probing, and I kept coming across the term Nuclear Anapole Moment (I think, it might be similar and I'm forget-remembering), but all the explanations I could find were really geared towards those who already have a better understanding of Nucleus structure than myself, or I was tired... either way I was hoping I might get a good answer seeing the quality of the usuals here. Background: I have undergrad in physics and starting a theoretical Master's soon.

edit: probing

submitted by /u/GiraffeNeckBoy
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What happens to a light ray after contacting with the surface of a solar panel?

Posted: 09 Jul 2019 06:47 AM PDT

Does travelling by train really pollute more than by car?

Posted: 09 Jul 2019 09:43 AM PDT

I saw this in an old Top Gear episode. They actually said that travelling by modern high speed trains polluted more than planes?

submitted by /u/Gorgar_Beat_Me
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What s the quantum mechanics explanation of the angles between the atoms in molecules?

Posted: 09 Jul 2019 09:26 AM PDT

Are there any diseases that are more common in one sex than the other that aren’t genetic or genital related?

Posted: 09 Jul 2019 01:16 AM PDT

If a person becomes dehydrated, can their body somehow "draw" from liquid in the bladder as a source of hydration without having to expel and drink it?

Posted: 08 Jul 2019 09:24 PM PDT

I'm wondering for example if I run out of water in the desert, would it be a good idea to try not urinating for as long as possible? Or is any excess water in the bladder already "spent"?

submitted by /u/Sw3dishFish
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Tuesday, July 9, 2019

How does your phone gauge the WiFi strength?

How does your phone gauge the WiFi strength?


How does your phone gauge the WiFi strength?

Posted: 09 Jul 2019 03:18 AM PDT

What's the reference against which it compares the WiFi signal? And what does it actually measure?

submitted by /u/geisvw
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What aspects of a speaker determine it's max volume?

Posted: 09 Jul 2019 04:28 AM PDT

Are the protons and neutrons in a specific isotope always arranged in the same/similar way?

Posted: 09 Jul 2019 05:42 AM PDT

My understanding is that neutrons help glue the protons together via the residual strong force, while also helping to spread the protons out to reduce coulomb repulsion by physically separating them. This makes a bit of sense, but from this interpretation then, it would seem to me that its not just the number of protons/neutrons in the nucleus that matter, but also (to an extent) the physical placement of the neutrons and protons with respect to one another. It would seem that an atom with ALL of its protons clumped together in a ball that is wrapped in a shell of neutrons wouldn't be stable, despite having the correct number of protons/neutrons. I know this is a rather extreme example, but the reason for giving it is that it makes me believe that just having the right number of protons and neutrons isn't enough. And it also raises a bunch of other questions for me such as:

- How many stable configurations are there for a given atom?

- Are protons/neutrons organized "rigidly" into a nearly spherical nucleus? Or can the shape of the nucleus change/deform (either with time, or maybe just being statically asymmetrical)?

- If the distribution of protons/neutrons is even slightly asymmetrical, wouldn't this give the nucleus some kind of dipole moment?

- Is the arrangement of the protons/neutrons always the same/similar for a given isotope?

- For extremely heavy elements that are already unstable to begin with, does variations in the distribution of protons/neutrons help to increase or decrease stability from atom to atom?

- Do protons and neutrons move around while in the nucleus, or are they more or less fixed in place?

Am I barking up the complete wrong tree here, and trying to push my classical views on a quantum system in a way that doesn't work?

Any kind of info would be greatly appreciated!

submitted by /u/ChrisGnam
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Why, when you brush your teeth right before going to bed, do you need to brush them again when you wake up in the morning? It feels as though you have drank two glasses of coca cola in your sleep.

Posted: 09 Jul 2019 02:08 AM PDT

When ancient language or code was deciphered, how did they know that it is correct?

Posted: 08 Jul 2019 05:42 PM PDT

Why was the Wheeler-Feynman absorber theory abandoned?

Posted: 09 Jul 2019 08:16 AM PDT

I'm starting to learn the basics of quantum mechanics with the goal to learn quantum field theory. As I understand, the concept of spin is fundamental to quantum theories, so I want to understand how people came to its discovery and how the formalism was derived and defined.

Being sceptical I also try to understand the history of the field concept. At first the field was just a background on which particles (as the atoms of matter/energy) acted, but only the particles were "real" (basically as the test subject of the field); so the field was an abstract concept, in the same way as "spin" is an abstract concept.

At which point was it decided that "the field(s)" is a real physical entity?

I understand that whatever error makes the formulation of a unified theory an impossible task, was made in the 1920s/1930s. It could be a simple thing like a translation error from German to English and back, it could be a logical/mathematical error in the definitions of the concepts. It could be the guilt of Dirac who ignored the discussions which led to the Copenhagen interpretation and just kept on working on a fundamentally wrong theory, but one which works almost perfectly.

And there's no out currently because everything works too well, nobody wants to give up the field. It reminds me of the switch from Geocentrism to Heliocentrism: Heliocentrism as a theory was worse back then, it took some time to iron out the problems.

It seems that Wheeler/Feynman didn't buy the foundations of the then current physics and tried to base a theory on the "action at a distance"; but it seems that it was abandoned, seeing the success of GR and QM.

submitted by /u/PinkOwls_
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Does the normal force between two objects affects the heat transfer between them?

Posted: 08 Jul 2019 10:16 PM PDT

It sometimes feels hotter when you press hard against something hot than when you lightly touch it. It got me thinking about whether the amount of normal force between two objects affects the rate of heat transfer between them.

Assume object A is at 0 degrees Celsius and laid down on a 100 degrees hot floor. Object B is identical to A in shape and initial temperature but has twice the mass, and laid down on the same floor. Will B heat up faster than A?

submitted by /u/hrsidkpi
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When you are pre-heating an oven, does the internal temperature rise at a fixed rate, or exponentially?

Posted: 08 Jul 2019 10:38 PM PDT

Does wiping off your sweat prevent the body from cooling down?

Posted: 08 Jul 2019 04:45 PM PDT

Does the cooling effect come from the sweat absorbing the heat on its way out or should you leave it and not wipe it to lower your temperature more efficiently?

submitted by /u/RocketRaptor
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Is it possible to accurately predict the magnitude of an earthquake by measuring the waves in backyard pools?

Posted: 08 Jul 2019 06:02 PM PDT

Is the Rutherford Scattering Experiment an example of Quantum Tunneling?

Posted: 08 Jul 2019 04:43 PM PDT

During the Rutherford Scattering Experiment particles went through a thin sheet of gold but some also reflected back. Is Quantum Tunneling one of the reasons for this?

submitted by /u/IcyFlameZ007
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How much oil is there?

Posted: 08 Jul 2019 03:48 PM PDT

How long untill our usage of oil depletes its reserves?

submitted by /u/oshigoroshi1
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How come we never sneeze while sleeping?

Posted: 08 Jul 2019 12:01 PM PDT

How do mosquitos know when to stop drinking blood so that they don't pop themselves?

Posted: 08 Jul 2019 04:21 PM PDT

Was the Chicxulub meteor a random stray, or was it from our local system?

Posted: 08 Jul 2019 01:00 PM PDT

Is it possible to tell the origin of the stellar body that caused the Chicxulub impact crater? Every recent bit of info available on Chicxulub suggests it could have caused the mass extinction of the dinosaurs (KT boundary etc.) I'm curious about how long it may have orbited Earth, if it had any super rare elements or minerals not found in the solar system, etc.

submitted by /u/CJShort
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How do we know which wavelengths are the eyes of other animals sensitive to?

Posted: 08 Jul 2019 03:18 PM PDT

For example, how did we find out that kestrels are ultraviolet sensitive?

submitted by /u/eppur-si-muove-
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If sand is basically tiny pieces of rocks, why is it that melting rocks doesn't create glass but melting sand does?

Posted: 08 Jul 2019 11:17 AM PDT