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Friday, December 15, 2017

Are the rocks in the asteroid belt between Mars and Jupiter the same kind of rocks you’d find on the earth?

Are the rocks in the asteroid belt between Mars and Jupiter the same kind of rocks you’d find on the earth?


Are the rocks in the asteroid belt between Mars and Jupiter the same kind of rocks you’d find on the earth?

Posted: 14 Dec 2017 03:47 PM PST

What is more energy saving? To connect a fully charged device to a power bank for it to keep it's battery full or to wait for the device's battery to deplete and then use the PW to charge it

Posted: 14 Dec 2017 07:21 PM PST

Edit: PB as in power bank, not PW

submitted by /u/SootheAndHeal
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What is happening in the brain when you are struggling to remember something?

Posted: 14 Dec 2017 01:49 PM PST

How do traditional filament lightbulbs fail?

Posted: 14 Dec 2017 03:50 PM PST

They have no moving parts, the filaments are protected from friction and corrosion ... what exactly is happening when they fail? What processes are involved?

submitted by /u/Gargatua13013
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Why is Paris warmer than Quebec City, despite being further north?

Posted: 14 Dec 2017 09:46 AM PST

Would it be possible to detect objects that are just outside the Observable Universe by the gravitational influence they would have on objects that are near the edge of the Observable Universe?

Posted: 14 Dec 2017 06:11 PM PST

How do GPS satellites handle so much data traffic?

Posted: 15 Dec 2017 04:22 AM PST

There has to be millions of people in a certain region using GPS at the same time.How do the satellites handle so much data and provide information to the user do quickly?

submitted by /u/Cipher216
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Do electrons exist at a specific place at a given time?

Posted: 14 Dec 2017 07:29 PM PST

I am having a difficult time getting a straight answer out of physicists for this question. I've been told by professors of physics and chemistry that an atom consists of a nucleus with electrons moving around it in orbitals and that we can't tell exactly where an electron is at any given time, we can only calculate the probability that an electron is in a given area at a specific time. Does this mean that the electrons don't exist at any specific place at a given time or is it just that we can tell where one is any given time. If it's just that we can't tell where one is at any given time but that they do exist at some specific place at any given time, is the reason we can't tell we they are just due to current technological limitations or is it believe that there are epistemological limitations to us ever being able to know where the electrons are at any given time regardless of how technologically advanced we become?

submitted by /u/DeutscherLerner
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Why are battery voltages selected at the values they are? What is special about 12, 5, or 3.7 volts?

Posted: 14 Dec 2017 07:42 PM PST

What effect does long-term exposure to darkness have on the senses?

Posted: 14 Dec 2017 04:10 PM PST

The senses I'm most curious about are sight, balance and Proprioception, though any information at all would be greatly appreciated :)

submitted by /u/-GoddessAthena-
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What does it take to leave the moons gravitational field?

Posted: 14 Dec 2017 12:58 PM PST

So I just saw the recordings of the Apollo mission leaving the moon and it got me wondering: what does it take to leave the moons gravity compared to leaving earth's? The Apollo had to first have enough combustion to slow down and land and then leave again. I know the gravity on the moon is several times les powerful than on earth but still it does not make that much sense to me. If we look at space x just now being ready to land a rocket again. How did they do it back in the day AND make it take-off again?

This probably makes me sound like conspiracy theorist, wich I'm not. I'm just genuinely wondering how this was possible back then.

Here is the video btw: https://www.facebook.com/IFeakingLoveScience/videos/2015291808491820/

submitted by /u/Mdpablo
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What are some of the tools used in big data management? What kind of analysis are to be done when analysts receive huge data dumps?

Posted: 15 Dec 2017 02:19 AM PST

Im curious as to what kind of tools data scientists use to draw meaningful conclusions, other than the usual use of variance, mean and other common statistical tools a common high schooler will use. Any links to educate a data greenhorn like myself?

submitted by /u/krankschaft
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How can temperature be negative?

Posted: 15 Dec 2017 01:21 AM PST

Are the reasons for grey matter reductions in brain during and after stressful life events documented?

Posted: 14 Dec 2017 04:01 PM PST

I mean for instance does prefrontal cortex lose grey matter due to some pruning mechanism of the brain ,due to excessive cortisol/glucocorticoids or some other reason?

submitted by /u/Periplokos
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How similar are the Bengal Tigers and Sumatran Tigers genetically?

Posted: 14 Dec 2017 05:59 PM PST

I'm writing a paper on the similarities between different species of big cats and I've found this bit of information quite hard to track down.

submitted by /u/Gaullic
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Magnetic fields and electric fields are manifestations of the same phenomena. They are inherently related. Is there a duality that exists between the gravitational field and something else? Thank you.

Posted: 14 Dec 2017 09:17 PM PST

Has anyone proved how many colors you would need if you had a cube with an arbitrary number of three-dimensional regions in it so that no two bordering regions are the same color? It would be like the four color theorem but in three dimensions.

Posted: 14 Dec 2017 12:31 PM PST

How large does an object have to be for it's gravity to noticeably affect light?

Posted: 14 Dec 2017 12:24 PM PST

If matter and antimatter annihilate and the result is gamma rays, can we reverse engineer this?

Posted: 14 Dec 2017 01:44 PM PST

What is the AdS/CFT correspondence?

Posted: 14 Dec 2017 09:07 AM PST

I know it deals with quantum gravity and quantum field theory, but can someone elaborate on this? As of 2015, Juan Maldacena's 1997 paper on the subject had over 10,000 citations, becoming the most highly cited article in the field of high energy physics. What was/is the significance of his paper?

submitted by /u/generallyrelative
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How do gamma rays make bad whiskey smoother?

Posted: 14 Dec 2017 11:10 AM PST

I asked the same question on another subreddit, but I believe you can answer it in more depth, also I love physics (am currently studying biochemistry), so if you have any related facts, I'd love to hear them.

I have read some articles on the internet that states if you irradiate bad whiskey with gamma rays, it will become much smoother. Also, if you irradiate cheap wine it loses it bitter aftertaste. You'd need about 200x the lethal dose for it to work. What is happening to the drink? Are all molecules afflicted by gamma radiation or just the less stable one's?

Because it is neigh impossible create gamma rays without a particle accelerator or radioactive isotopes I thought would x-rays suffice, albeit having a lower energy than gamma rays, it is still ionizing radiation. All because making x-rays at home is (a bad idea) in the realm of possibilities thanks to ebay.

Bonus fact: During my own "googling" to answer this question I stumbled upon this neat fact. Glass can be stained black by gamma rays, by heating it afterwards it becomes transparent again :)

submitted by /u/Faultybrains
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How is the focal length of a gravitational lens determined?

Posted: 14 Dec 2017 10:17 AM PST

This question cropped up last weekend, and I had no idea how to solve it. Can somebody give me some pointers here, or point me to the right references? Thanks!

submitted by /u/sw_dev
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What are the reasons for the observed decline in brain volume over the course of the last 20000 years?

Posted: 14 Dec 2017 07:02 AM PST

When asked I assumed it was due to the fact that we were witnessing an evolutionary process, that our brains were shrinking but becoming more efficient. But this doesnt seem to be the case. Furthermore I read that the decline in brai size is even more significant with women than men. Any solutions????

submitted by /u/wolfgertripathi
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Thursday, December 14, 2017

Does a burnt piece of toast have the same number of calories as a regular piece of toast?

Does a burnt piece of toast have the same number of calories as a regular piece of toast?


Does a burnt piece of toast have the same number of calories as a regular piece of toast?

Posted: 13 Dec 2017 09:48 PM PST

What causes mental fatigue and how does it compare to muscular fatigue?

Posted: 13 Dec 2017 09:11 PM PST

How do we know that gravity has infinite range?

Posted: 13 Dec 2017 09:16 PM PST

can someone who suffers from Alzheimer dream?

Posted: 14 Dec 2017 03:51 AM PST

What is the Correlation length of Temperature?

Posted: 14 Dec 2017 05:55 AM PST

Cities that are close to one-another will have temperatures that are correlated; a hot day in one will likely be a hot day in the other. Cities that are farther apart will generally have uncorrelated temperature, except due to global fluctuations (December is colder than July in both New York and LA). So, what is the typical correlation distance of temperature?

Just playing around with Wolfram Alpha, Chicago and New York look uncorrelated, New York and Boston are totally correlated, whereas New York and Detroit are weakly correlated. So, I estimate the correlation length at about 1000 km, but I imagine it's different EW vs NS.

submitted by /u/iorgfeflkd
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Why is going on your tip-toes easy, when doing a push-up is difficult?

Posted: 13 Dec 2017 08:35 PM PST

I was just sitting in a position like this and was slowly raising and lowering myself on my toes as a sort of stretch. After a little bit, I began kind of freaking myself out, because it feels like I'm lifting my entire bodyweight using only my toes.

Why is this so simple to accomplish, when a different way of moving your body up and down (a push-up) is relatively difficult?

DISCLAIMER: I feel like this is a very dumb question. I wish I could say that I'm drunk or something, but no, I'm just in my room raising and lowering myself on my toes.

submitted by /u/justlikejohnnymarr
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Is there a sequence of moves that can be applied to a Rubik's Cube that results in iterating the cube through every possible state exactly once?

Posted: 13 Dec 2017 11:00 PM PST

Have any animals developed projectiles?

Posted: 13 Dec 2017 06:24 PM PST

Whether through technology or through bodily functions.

submitted by /u/quackbass
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Did the construction of the LIGO gravitational wave detector account for the curve of the earth? Did each end of have to be risen up a bit so that each light beam was perfectly straight?

Posted: 14 Dec 2017 12:07 AM PST

How can a supernova get brighter, even after it's "peak brightness"?

Posted: 14 Dec 2017 03:47 AM PST

I found a graph comparing the brightness of different kinds of supernova brightness'. The link is from another post in this subreddit and i don't claim any rights to it. I was just interested in how thy behave. Sorry for poor english.

From here: https://physics.stackexchange.com/questions/61872/how-long-does-a-supernova-last

submitted by /u/Numree
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How much electricity can travel on a transmission line?

Posted: 13 Dec 2017 09:26 PM PST

I'm trying to understand electricity transmission using an analogy of distribution of water. In this case the transmission lines are the pipes, but what would their capacity be? If I say the lines are 138kV for example does thst give me any idea of how 'big' the pipe is, and therefore how much electricity I can transmit per unit time?

Thank you!

submitted by /u/monkeyjazz
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What is information and why is it lost in a black hole?

Posted: 13 Dec 2017 11:51 AM PST

Do other mammal species, like pigs, have an Adam's apple?

Posted: 13 Dec 2017 07:33 PM PST

How do we know black holes can die if we have yet to see it happen?

Posted: 13 Dec 2017 04:40 PM PST

I've been searching for a minute and I can find plenty of information suggesting that black holes will eventually evaporate, I can't find any info on when or where the evidence we have for it is other than extrapolated equations.

I'm mostly just unsettled by the fact that I can't seem to find any evidence of black holes completely evaporating and I get worried about our universe.

submitted by /u/Servicemaster
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Is there any way to, overnight, neutralize or otherwise nullify the danger of the Elephant's Foot in Chernobyl?

Posted: 13 Dec 2017 09:33 AM PST

the -admittedly brief- wiki page states that Chernobyl's Elephant's Foot "will remain radioactive for over 100,000 years".

if cost and resource availability were not an issue, would there be any way to neutralize such an intensely dense and radioactive site/object overnight (or in a reasonably brief amount of time)?

side question: what is currently being done about it, and in what ways are scientists trying to make future progress in dealing with it?

submitted by /u/BartlettMagic
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If a nuke explodes mid-air, does the mushroom cloud still form?

Posted: 14 Dec 2017 01:46 AM PST

Is it possible to refine iron ore in a vacuum?

Posted: 13 Dec 2017 09:12 PM PST

Why do the bottoms of glass beer bottles pop off when tapped?

Posted: 14 Dec 2017 12:57 AM PST

I just saw this post https://www.reddit.com/r/instant_regret/comments/7jmhe4/there_is_always_that_unlucky_friend/ and I see that the top comment explains it as heating but I don't think that's it, looking at the delay, the heating may have made it weaker but I think it's the same effect. I have seen people do this with soda bottles before.

For that matter I remember that post where the guy talks about what happens if a glass was actually half vaccum at the bottom and half water at the top. Is this similar in anyway?

submitted by /u/Anantgaur
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Where are quantum behaviours/phenomena (coherence, entanglement, etc...) actually occurring outside of controlled laboratory conditions?

Posted: 13 Dec 2017 11:52 AM PST

Given the general "noisiness" of everything happening within our own bodies, across the surface and within the atmosphere of the planet, and the relative "warmess" and "non-emptiness" of even interstellar space (bottoming out somewhere around 2.7 Kelvin and home to oodles of molecular hydrogen?), are the overwhelming majority of fundamental particles which compose matter always in a state of decoherence, and as such never exhibiting any quantum behaviour?

I imagine that light, given that it obeys Bose-Einstein statistics is often exhibiting quantum behaviour during travel, but I really have no idea.

Basically I'm wondering where and to what extent are quantum behaviours occurring "naturally" (ie. outside of controlled laboratory conditions).

I'm just a layman with an interest, so I apologize if this question doesn't make too much sense, I'll try and elaborate if necessary.

submitted by /u/50millionfeetofearth
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Wednesday, December 13, 2017

How were roots and logarithms inititially calculated without the use of calculators?

How were roots and logarithms inititially calculated without the use of calculators?


How were roots and logarithms inititially calculated without the use of calculators?

Posted: 12 Dec 2017 09:51 PM PST

Right now all I do is use the root, log or ln button in my calculator and it spits the answer out. Is there a systematical way of calculating this by hand?

submitted by /u/Magisidae
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How long does a supernova last?

Posted: 13 Dec 2017 04:33 AM PST

If a star exploded near enough to Earth for us to be able to see it, how much time would we have to enjoy the view before the night sky went back to normal?

submitted by /u/VelvetPoltergeist
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What selection pressures caused gender/sex to evolve?

Posted: 13 Dec 2017 02:19 AM PST

Since life came from a single celled organsim, what are the selection pressures that could've caused mutations/genes that resulted in genders?

Bonus questions I'd much appreciate if you could answer:

  • What selection pressures along with changes in genes caused different developments of sexual reproduction mechanisms? In essence how is it that some species reproduce in a manner that is completely different from a species whom not long ago came from the same ancestor?

  • Are their species where more than two genders/sexes evolved?

Thanks in advance.

submitted by /u/962rep
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Why isn't the atmosphere of Jupiter homogeneous?

Posted: 12 Dec 2017 06:24 PM PST

After what I would assume is a few billion years of mixing, why are there still such defined patterns in Jupiter's atmosphere? Why are the layers not homogeneous? Does it have to do with updrafts mixing more dense layers?

submitted by /u/Now_Plain_Zero
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What do the dot product/the tensor product of two vectors represent geometrically?

Posted: 12 Dec 2017 07:50 PM PST

So the cross product isn't too hard to understand conceptually, since there's an actual geometric representation for what it is (if a x b = c, then c is perpendicular to a and b and has a magnitude equal to the area of the parallelogram made by a and b (E: that goes in the direction according to the right-hand rule)). But what about the dot/tensor product? I know how to do them, but what exactly do they represent geometrically?

submitted by /u/Popopopper123
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How do ISP's limit the speeds I get?

Posted: 12 Dec 2017 05:27 PM PST

Is there any element that can form 8 or more covalent bonds?

Posted: 13 Dec 2017 05:49 AM PST

Or is the maximum permissible bonds seven like in IF7?

submitted by /u/DeltaEmerald11
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Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science

Posted: 13 Dec 2017 07:07 AM PST

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Physics, Astronomy, Earth and Planetary 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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Does the gritting/salting of our roads during winter have any significant impact to the salination of the waterboard?

Posted: 13 Dec 2017 02:45 AM PST

What is our best information about the origin point of intersteller asteroid Oumuamua?

Posted: 12 Dec 2017 10:20 AM PST

The first information I cam across (more than one science journalism source) suggested the star Vega, in Lyra. This seems pretty specific. Another source suggested that this thing had been travelling for so many billions of years that if it came from the area of sky that is now occupied by Vega, Vega wouldn't have been there at the time.

More recent updates have suggested the southern constellations of Carina and Columba. I don't have any astronomy-related training at all, but isn't that that a completely different chunk of sky?

...new here; hope I followed all the correct formats.

submitted by /u/tygrebryte
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Whats the difference between liquid and gas?

Posted: 12 Dec 2017 11:34 AM PST

I know this many sound like an extremely simple question, but on a molecular level, what's the difference between a liquid and a gas? From a young age we're shown a collection of diagrams showing how the structure of molecules in solids, liquids and gases differ. In diagram of the solid, they're touching, in the liquid, they're spaced apart and less structured, and in the gas, they're even further apart. My assumption has always been (feel free to correct me if I'm wrong), that difference between a solid and a liquid is the molecules 'touching', there molecular bonds. When a substance becomes hot enough that's its molecules have enough energy to break there bonds, it becomes a liquid. We have a definite point in which a solid becomes a liquid. Equally, there is a definite point when a gas becomes a plasma, when the molecules gain enough energy that there atomic bonds begin breaking down, making a soup of protons electrons and the works. ...but what's the definite point between liquid and gas? Are there any properties that a gas has the a liquid does not? Theoretically, if we had a liquid and a gas of the same density, how would they behave differently? Maybe a slept though a key part of my year 6 science classes and missed something. Help me atone for my younger laziness reddit!

submitted by /u/Flyingnutkick
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How can you make antimatter in a particle collider?

Posted: 13 Dec 2017 01:23 AM PST

I understand that you can find new sub particles by hitting two hadron together in near light speed such as higgs boson. But how can you reverse the electric charge of an atom in that way?

submitted by /u/Numree
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Do we all see the same color when looking at the same thing?

Posted: 12 Dec 2017 02:02 PM PST

We all know the grass is green, but could someone's "green" be someone else's red or blue? Do other people see things in various different colors but associate that color by the same name we've always known it as?

submitted by /u/LightWithoutLaz
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If axial tilt causes the seasons at temperate latitudes, then why don't the poles experience extremely hot summers when the sun is out all day, and even *more* extreme winters when the sun remains set all day?

Posted: 12 Dec 2017 03:05 PM PST

Are earthquakes worse if you are many stories above? Or if you are many floors underground?

Posted: 12 Dec 2017 06:56 AM PST

Is it possible to use The Hubble Telescope to look at the interstellar asteroid in our solar system?

Posted: 12 Dec 2017 10:36 AM PST

I've seen that SETI want to use radio telescopes to listen to the first interstellar object in our solar system (that we know of), would it be possible to use the Hubble Space Telescope to get a better look of it?

submitted by /u/Killco_Joe
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Does temperature have an effect on cables like HDMI or ethernet? If so, how?

Posted: 12 Dec 2017 07:05 AM PST

For example: say you routed an ethernet cable from a computer to a modem. The cable lays above a heater which then another section of the same cable lays in front of, say, a door to the outside which cold can come through. Then the rest of the cable goes into a computer.

Would the cold and heat do anything to the connection or the cable itself in general?

submitted by /u/PM_For_Help
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Have the Hawaiian islands gotten bigger or smaller over time?

Posted: 12 Dec 2017 01:57 PM PST

Have they gotten smaller because of global warming? Were they larger or more prominent 150 years ago before industrialization? Is it possible their size would change regardless given their geographical location? Are they going to disappear and what may cause that?

submitted by /u/emsiii
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Are there any "rock-paper-scissors"-genes?

Posted: 12 Dec 2017 06:12 AM PST

I'm in my last year of high school, and learning about genetics. So far, we've covered dominant and recessive genes, as well as codominance and such. Are there any genes where the alleles dominate each other like in a game of rock-paper-scissors?

submitted by /u/Mirriet
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How does the geographical spread of influenza work?

Posted: 12 Dec 2017 01:22 PM PST

I've always thought of influenza as a cold weather illness, which by and large, it seems to be. Australia was hit particularly hard this winter, and now that the seasons are changing, they're seeing a slowdown.

Now, the northern hemisphere is starting to get sick, and I was looking at the map of the US on the newest CDC report. I've always known it tends to start in the southern US and work it's way up, but why is that? Do we know? Areas where it is truly the coldest right now have sporadic cases, but the deep south is already at high levels. If it is a cold-weather illness, why doesn't it start spreading the fastest in the areas that are the coldest, where people are shut in and spreading germs already?

submitted by /u/tinygiggs
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