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Monday, February 12, 2018

How do stains work on the molecular level?

How do stains work on the molecular level?


How do stains work on the molecular level?

Posted: 11 Feb 2018 04:37 PM PST

How are the particles that become stuck on clothing so difficult to remove? And as a follow up question, how do stain removers work?

submitted by /u/thebossadam
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How do directions work in space?

Posted: 11 Feb 2018 04:30 PM PST

On Earth we have north, south, east, and west, but those are relative to Earth. What directions, if any, do people use for space?

submitted by /u/thiskid888
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What is the social behavior of tardigrades? Do and if so, how do tardigrades interact with one another?

Posted: 12 Feb 2018 05:32 AM PST

Googling doesn't answer that question and the literature on Google Scholar and pubmed is too high of a threshold to dig through for me as a layperson.

submitted by /u/Megaflarp
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How did the Apollo spacecrafts get past the Van Allen Radiation belt?

Posted: 11 Feb 2018 02:02 PM PST

Had a family friend tell me about this and I wanted to know if you guys have the answer to this .

submitted by /u/RocketFarmaHerbs
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Do animals have a dominant "hand" like humans do?

Posted: 12 Feb 2018 12:00 AM PST

In deserts and beaches, why do dunes form instead of the sand uniformity flattening out?

Posted: 11 Feb 2018 08:08 PM PST

Correlation vs. covariance difference?

Posted: 12 Feb 2018 02:01 AM PST

I get all that so far. So they're 2 different tools that perform the same job. Besides the cases of having different measurements, which covariance is unable to do,

1) why would any prefer covariance over correlation or vice versa? In what situation would be more fitting to use one over another?

2) so what does the numerical result in covariance means? I know if it's positive or negative than it's related or inversely related - same for correlation. In corrl, we can intuitively understand that 0.5 means if A moves by 1 B moves by 0.5. But it doesn't explain what the number means in covariance.

3) why do we need both?

submitted by /u/TriLamSr
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What happens in the digestive system of animals that eat other animals whole?

Posted: 11 Feb 2018 08:59 PM PST

When an animal eats another animal whole, what happens in the stomach of the predatory animal? It's difficult to imagine an entire prey animal stuffed into a stomach and digested without any complication or interesting process behind it.

Edit: word.

submitted by /u/LurkLert
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How does the subducted oceanic lithosphere retain its shape and form in the asthenosphere?

Posted: 12 Feb 2018 06:19 AM PST

From what I saw on the diagrams used for subduction zones, oceanic lithospheres stay solid even under hundreds of kilometers in the mantle, but how does it survive the intense heat without melting thoroughly?

submitted by /u/WeirdSymmetry
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Did we learn anything new about Jupiter from Shoemaker/Levy 9 colliding with it?

Posted: 11 Feb 2018 01:58 PM PST

Follow-up: If it occurred today, would modern instruments have gathered any extra, meaningful data from it?

submitted by /u/TacosArePeopleToo
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Are there cryovolcanos on Titan?

Posted: 11 Feb 2018 06:25 PM PST

I read a few years ago that there was a debate in the scientific community for the presence or absence of cryovolcanoes on Titan, with some pointing to images taken by Cassini as evidence for past cryovolcanic activity. Is there currently any sort of consensus on this issue?

submitted by /u/harmonium1
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Given a completely sealed, non-insulated container filled with liquid nitrogen, would the container be cold forever?

Posted: 11 Feb 2018 04:55 PM PST

If the theoretical airtight container existed to contain liquid nitrogen in perpetuity, what would happen to the liquid nitrogen over time? Would the walls of the container continue to be cold forever?

submitted by /u/aisle-is-closed
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Why are some tumours benign and other tumours not benign in the human body?

Posted: 11 Feb 2018 04:47 PM PST

What do we know about dark matter and dark energy during the big bang?

Posted: 11 Feb 2018 07:15 PM PST

I understand the theory that all known matter was in a singularity 14 or so billion years ago and dark matter hasn't been directly observed, but is the prevailing evidence it was in the singularity as well? Are there ideas out there that suggest otherwise?

submitted by /u/Cartoon_Cartel
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How are this sort of rocky boulder hills formed?

Posted: 11 Feb 2018 11:19 PM PST

Hi reddit, i live in an area with many rocky hills, my pals and i have always wondered how they were formed. I have a bet that the area was under water many years ago!. https://bucketlist.co.ke/travel/uploads/2017/04/Lukenya-5.jpg

submitted by /u/sideshowtoma
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How come some avian pathogens can pass so easily to primates like us? Is there some Immunological similarity?

Posted: 11 Feb 2018 01:08 PM PST

With how popular renewable energy is becoming why do we hear so little about superconducting power cables?

Posted: 12 Feb 2018 02:31 AM PST

From my understanding the big problem with superconductors is that you need to cool them down to a very low temperature, however that seems like a static loss largely regardless of how much energy you send through them. So why don't we have/are working on intercontinental cables between Asia, Europe,Africa and maybe even under the sea to Australia and the Americas to transport renewable energy through. The sun is always shining somewhere on earth so wouldn't this be a good alternative to trying to store the energy?

I know that they tried it in Essen but haven't heard about any attempts to scale that up

submitted by /u/thijser2
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Why does albinism appear across species?

Posted: 11 Feb 2018 06:57 PM PST

I saw a picture of an albino animal and was curious as to how different species all have a similar genetic mutation. It was especially puzzling considering it would be a disadvantage in terms of hiding. So how do a multitude of species have some individuals with very similar genetic defects namely albinism?

submitted by /u/notimeforfunandnames
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Why is the asteroid belt a ring and not a bubble?

Posted: 11 Feb 2018 10:05 PM PST

Space is obviously 3D, so why does the asteroid belt seem to be on a plane.

Follow up Question: are the planets on the same plane as well?

submitted by /u/-SickDuck
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How much space is there in between particles in a gas cloud in space that is many light years in size?

Posted: 11 Feb 2018 06:59 PM PST

Suppose I'm floating within one of these gas clouds. Would it seem foggy or would it appear no different then if I was an an empty area of space?

submitted by /u/Soup0988
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Why do tank treads have to be asymmetrical to drive straight?

Posted: 11 Feb 2018 02:05 PM PST

This may be outdated, but I'm reading Boys for Men, a memoir of a Vietnam era tank driver who was on m48s and sheratons later. He Talks about removing one tread block from one side when he gets the Sheraton, because it makes it "toe in" and drive straight. The other guys with less training didn't do this and their tanks had trouble. I kind of vaguely know what toe is on a car, but I'm not sure how this removing a block changes the toe on a tread. Or, really, why don't the tank designers do this or add an adjustment mechanism so the grunts aren't repairing the treads in the jungle.

submitted by /u/jvttlus
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Sunday, February 11, 2018

Does the language you speak affect the shape of your palate?

Does the language you speak affect the shape of your palate?


Does the language you speak affect the shape of your palate?

Posted: 10 Feb 2018 08:49 AM PST

I was watching the TV show "Forever", and they were preforming an autopsy, when they said the speaker had a British accent due to the palate not being deformed by the hard definitive sounds of English (or something along those lines) does this have any roots in reality, or is it a plot mover?

submitted by /u/AleksioDrago
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How much 'stuff' is in space between the Earth and Mars?

Posted: 11 Feb 2018 04:38 AM PST

I had a student ask how empty space is, and I told them I really did not know. So, in an area like the orbital path between Earth and Mars (leaving out human space junk) how many objects would you find? Any? None? added question, if anyone knows: How much stuff is in true outer space - beyond out solar system, how often might you encounter an object of any size? Thanks

submitted by /u/POCKALEELEE
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Does the size of an object passing through the sound barrier have an effect on the force of the shock wave?

Posted: 11 Feb 2018 06:51 AM PST

I know from the Space Shuttle that the length of the vehicle produced a double shock wave. What - if any - would be the difference between, say, a baseball crossing mach 1 versus a Range Rover?

submitted by /u/Anticipator1234
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How do vegetables like asparagus and brussels sprouts effect the scent of urine?

Posted: 11 Feb 2018 05:57 AM PST

Why can icicles drip when it’s below freezing?

Posted: 10 Feb 2018 08:18 AM PST

In the upper Midwest right now and the temperature has been in the mid-20s for a few days, but all of the icicles around my house are dripping. Is this truly "melting," or is it something else? Thanks!

submitted by /u/qui505092
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Why are Saturns rings all on the same plane?

Posted: 10 Feb 2018 09:50 AM PST

Does hybridization occur in all valence bonds? If not then how do you identify where it happens?

Posted: 11 Feb 2018 12:35 AM PST

Is it impossible for something with 2 equally probable result, like a perfect coin toss, to only give one result given any number (and/or infinite amount) of trials?

Posted: 11 Feb 2018 06:26 AM PST

How does rubbing alcohol “dry out” rubber?

Posted: 11 Feb 2018 06:11 AM PST

It's frequently referred to as "drying out" rubber, but I can find references that say it's actually making it less elastic. What's happening?

submitted by /u/redneckrockuhtree
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Why would male snowboarders go downhill faster than female snowboarders?

Posted: 11 Feb 2018 02:15 AM PST

Discussing a challenging course, a commentator on Australian Winter Olympic coverage said that male snowboarders go downhill faster than women.

What would be the reasons for a significant difference in speeds between the men and women?

submitted by /u/jamesfromaustralia
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What determines what a particle decays into?

Posted: 10 Feb 2018 07:39 PM PST

For example, the Tau can decay into a tau neutrino and other particles each with their own probabities. What tells it to decay into a charged pion or an electron and electron antineutrino?

submitted by /u/GrayOctopus
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Is it possible that an asteroid or comet would approach the earth so fast that we'd be unable to observe and predict it at all?

Posted: 11 Feb 2018 01:29 AM PST

What effects did the weight and size of a dinosaur have on the type of environment it needed to support it?

Posted: 10 Feb 2018 07:53 AM PST

I am not 100% sure I used the right flair, if another would be more appropriate, please change it!

I used to drive semi trucks, and one of our major rules was never leave a loaded trailer on anything but concrete, because it's supports would sink into the ground on anything else.

In addition to that, I play and watch a number of scifi mecha type games, movies, and anime, and the discussion always comes up how mecha are unfeasible especially when they get big, because the ground wouldn't support their weight focused on where their feet were.

That had me wondering if the huge multi-ton dinosaurs had similar problems. I am interested in hearing anything about how their mass/size/weight effected them.

submitted by /u/Cryhavok101
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Do photons lose energy one go, or they gradually lose energy until they're completely absorbed by objects?

Posted: 10 Feb 2018 09:49 PM PST

I am not sure if I have framed the question right.

In a well-lit room, there's a continuous supply of 'fresh' photons from the light source, but the room doesn't get brighter (after a certain point). This is because photons are constantly absorbed by objects kept in the room.

My question is: does an individual photon lose energy in one go, when it gets absorbed by an object? Or, does it keep losing energy as it bounces off objects, until it's completely absorbed?

submitted by /u/sirabai
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How can people create such long telegraph cables without the powering fading out at the other end?

Posted: 10 Feb 2018 03:06 PM PST

Copper (Which what telegraph cables are made of) cannot carry electricity for long distances, It will fade out.

If you put too much power through it will burn up so how did they do it?

submitted by /u/olliegw
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Why do sedimentary rocks have such perfect stratification?

Posted: 10 Feb 2018 08:06 AM PST

Driving around you see cutouts through sedimentary formations and the different layers are pretty cool, but why are they distinct layers? Why is it not just continuous if it was being laid down consistently over time? - and what's with the wildly different types of rock being right next to one another? It's like for millions of years you had one sort of rock being laid down then, poof, now for something completely different!

submitted by /u/Flying_madman
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What determines when we have to pee?

Posted: 10 Feb 2018 07:58 AM PST

When we pee we don't excrete the same amount of fluid each time, so the procces of determening when you have to pee can't only rely on when the blader is full can it?

submitted by /u/biscuwit
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If multiple jupiters collided, how long would it take for the material to settle allowing fusion to occur?

Posted: 10 Feb 2018 01:19 PM PST

Is a singularity a discontinuity in spacetime?

Posted: 10 Feb 2018 09:58 PM PST

Blackbody radiation, how does it work?

Posted: 10 Feb 2018 08:57 PM PST

This chapter about light interactions with matter in my astronomy textbook is only 10 pages but it's taken me hours to understand. Ive watched videos but they get too complicated with stuff i havent heard of or isnt in this textbook.

This is what i understand for the most part: an object glows when it gets hot because the neutrons colliding give off electromagnetic radiation. As the temperature rises the color of the glow changes from red to yellow to blue.

Why do moving and coliding particles give off electromagnetic waves such as visible light or infrared?

Why do colder objects give off longer waves and hoter objects give off shorter waves?

Does an object have to be black to be a blackbody?

Do all objects give off blackbody radiation?

If stars can be so hot to be red, yellow, or blue does this mean they are or near black in color? If so what makes a star black? Can a star be invisible to our eyes by emiting only ifrared or UV light?

Basically i understand what is happening to a blackbody object, i just dont get why it happens or what makes it happen to one object and not another.

Another thing from this chapter that is less relsted to astronomy:

Atoms can obsorb photons if the wavelength of the photon has the right amount of energy. Waves without the correct energy just get bounced off, right? Is the bouced off wave the color we see with our eyes?

in the book it says an atom that obsorbs a photon of the corect wavelength becomes unstable(due to neutron changing levels) and re-radiates the photon in a random direction. If the atom is constantly re-radiating photons of different waves how does something stay one color? This confuses me as well.

submitted by /u/Jordan_ddddd
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Why do buildings sometimes have angled concrete columns (picture of example included)?

Posted: 10 Feb 2018 10:49 AM PST

I've seen a lot of buildings lately with angled concrete columns like the columns on the ground floor of this building: link. Why are columns sometimes angled like this?

submitted by /u/sepp_blatter_123
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How many percent of the Sun's radiation is generated by proton-proton fusion, and how many percent by electron-positron annihilation?

Posted: 10 Feb 2018 11:44 AM PST

Saturday, February 10, 2018

Why can't we simulate gravity?

Why can't we simulate gravity?


Why can't we simulate gravity?

Posted: 09 Feb 2018 08:29 AM PST

So, I'm aware that NASA uses it's so-called "weightless wonders" aircraft (among other things) to train astronauts in near-zero gravity for the purposes of space travel, but can someone give me a (hopefully) layman-understandable explanation of why the artificial gravity found in almost all sci-fi is or is not possible, or information on research into it?

submitted by /u/unlikely_baptist
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When the brain receives a nerve signal from the skin, how does it differentiate between a heat signal, a cold signal, a pain signal, a pressure signal etc?

Posted: 10 Feb 2018 03:54 AM PST

Is it "code-based", like different levels/durations of charge?

Is it "structure-based", like the pain-detecting nerves are connected to a pain-detecting piece of brain?

Or something else entirely?

submitted by /u/shit_post_life
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Since friction originates from electromagentic force, does that mean that neutrons, Which are neutral to each other, can overlap?

Posted: 10 Feb 2018 03:05 AM PST

Overlap = exist in the same spot in case it isn't clear.

This question can be taken a step further, since the force that keeps protons together should be stronger than the force that repels them (otherwise there are no atoms). Would that mean that protons in an atom should be compressing into a single point so that the nucleus has the volume of a single proton?

submitted by /u/guyuz
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What is the best way to plot the geometry of multiple intersecting magnetic and diamagnetic fields?

Posted: 09 Feb 2018 08:24 AM PST

Example of some practical questions to tackle are those presented in these demonstrations:

https://www.youtube.com/watch?v=sENgdSF8ppA

Essentially how could you plot the path that electrons are taking when a magnets interact with eachother or when they interact with a diamagnetic.

Georgia State University hosts a basic example of magnetic fields which likely we have all seen before: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magforcon.html

But how do we mathematically plot and predict how a magnetic field will behave when subjected to multiple sources in various amounts of Tesla units and their interactions with diamagnetic material?

Thanks Science!

submitted by /u/Fox_Tango
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Why are alpha particles invariably emitted from unstable nucli rather than individual proton or deuteron or 3He ?

Posted: 10 Feb 2018 01:54 AM PST

i know about the binding energy term and stability of alpha particle in comparable with the proton, 3He,deuteron.

submitted by /u/Shehab3055
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Why does planet's mass affect it's speed around sun?

Posted: 10 Feb 2018 06:08 AM PST

Let's assume that planet orbits sun perfectly circular. If force by which sun pulls planet is GMm/r2, and F=ma than a = GM/r2. Now we also know that for circular motion: a = V2 / r , which means that V = sqrt(r * GM/r2) So from this equations it seems that mass of the planet shouldn't matter at all. But I know that mass of the planet does matter if it's quite large, how? why? I mean are this laws incorrect? or do I miss something?

submitted by /u/cannabis_Grower
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What speeds do particles in the center of an atomic blast achieve?

Posted: 09 Feb 2018 05:13 PM PST

How do they compare to the velocities of particles in an experiment at the LHC?

submitted by /u/throwmeawaygoddam
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Has there been any proof to a preons existence? And exactly what is it?

Posted: 10 Feb 2018 03:51 AM PST

How are we sure how many protons/neutron an atom has?

Posted: 09 Feb 2018 12:03 PM PST

What is the center of mass for a ring? For example, if we built a massive ring world, without any artificial gravity, where would gravity take us?

Posted: 09 Feb 2018 04:46 PM PST

What is 0 divided by 0?

Posted: 09 Feb 2018 07:45 PM PST

I know that that a number divided by zero is undefined, but also a number divided by itself is also supposed to be 1. There is another way to look at it as well; what number times 0 will equal 0 which is every possible number. So which is it? I felt this was a better place to post than theydidthemath or estimation, let me know if I should ask over there as well.

submitted by /u/callmemateo
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Does the Milky Way Galaxy orbit around anything?

Posted: 09 Feb 2018 01:24 PM PST

Ok, so the fact that the earth orbits the sun is trivial enough. Then the sun orbits around the center of the milky way (side note, I would love for more information about this if anyone has it available). But, does the Milky Way itself rotate around some even larger object? And if so, is there a consensus, or at least theories, on how far it goes in this manner? Thanks in advance!

submitted by /u/RyanBrawny
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Orbital mechanics question: can you burn for a direct capture of mars orbit as you leave earth orbit?

Posted: 09 Feb 2018 01:22 PM PST

A friend and I got into a discussion about this. He says its impossible to do without a significant retro burn. I say it's just requires a lot of precision and is impractical but possible. What say you?

submitted by /u/jebediah999
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What happens when the sound barrier is broken at or around absolute zero?

Posted: 09 Feb 2018 11:06 AM PST

Basically, I just want to know if it is any different from breaking the sound barrier at normal conditions. Has this been done? I have read that it is easier to break the sound barrier at lower temperatures and lower pressures.

submitted by /u/MadZack
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If you push a heavy object in space, would you both be pushed at an equal distance or would you be pushed further?

Posted: 09 Feb 2018 08:13 PM PST

What are the hypothetical properties of gravitons, and what are their implication?

Posted: 09 Feb 2018 03:57 PM PST

I've heard from some various sources (not sure about their validity though) that certain energies and forces have an complementary particle (I.e. photons and light waves), and heard that the complementary particles to gravity are called gravitons. what hypothetical properties would these have, and what would that implicate according to those properties (I.e. for future research)?

(Sorry I'm on the app and it was bugging so I deleted my initial post, I am re-uploading it now)

submitted by /u/lithium_gold
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Is fusion actually happening inside of fusion test reactors?

Posted: 09 Feb 2018 01:37 PM PST

I've seen lots of headlines about working fusion reactors, but they all seem to beat around the bush in stating whether or not fusion is actually happening; the most press sites are willing to state is that generating "first plasma" was successful.

Is fusion going on inside of the reactors? How can we tell? Has fusion ever been successfully observed on earth?

submitted by /u/overtheridge
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Why can't we simply melt uranium metal to separate out the U-235? (Enrich it)

Posted: 09 Feb 2018 01:50 PM PST

We currently use things like a centrifuge to separate out the enriched U-235 from the U-238, because the U-235 isotope is slightly lighter.

As I understand it, the 2 isotopes are chemically identical, so the only way to separate them is by their (very)slightly weight difference.

Why can't we just melt a bunch of uranium and then let it settle in it's liquid form and scrape the U-235 "cream" off the top?

submitted by /u/Omniwing
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What languages are the most efficient and inefficient ones?

Posted: 09 Feb 2018 09:56 AM PST

In other words: what languages has, on average, the longest sentences?

submitted by /u/datttPenGUiN
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How do stars die?

Posted: 09 Feb 2018 03:51 PM PST

How are lab rats given cancer?

Posted: 09 Feb 2018 01:24 PM PST

How did the scientists who made the cancer vaccine get the mice to have cancer?

Posted: 09 Feb 2018 07:15 PM PST

How worried should we be about melting permafrost releasing mercury?

Posted: 09 Feb 2018 10:54 AM PST