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Monday, January 7, 2019

How do the Chinese send signals back to earth from the dark side of the moon if it is tidally locked?

How do the Chinese send signals back to earth from the dark side of the moon if it is tidally locked?


How do the Chinese send signals back to earth from the dark side of the moon if it is tidally locked?

Posted: 06 Jan 2019 08:46 AM PST

Why are almost all of Earth's time units multiples of 6?

Posted: 07 Jan 2019 05:43 AM PST

Is it coincidence or scientific or just a completely invented concept by humans?

submitted by /u/pancakeghost12
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Given an equivalent surface area to compare, are meteorite impacts more likely to happen around the equator, or at the poles?

Posted: 06 Jan 2019 08:12 AM PST

I was recently thinking about the likelihood of a meteorite impact where I live. Then, it got me thinking: on a geological time scale, are these impacts more likely to happen at the equator (given most of the stuff in our local region is orbiting the sun around the same plane that the earth and its equator is), or at the poles?

I realize that the effect of precession and the tilt of the poles into and out of the vector of the Earth as it travels around the sun does increase the chances of seasonal meteor showers in certain parts of the world. Also, I'm aware that the time of day also changes the likelihood of meteorite impacts, again because of the Earth's direction of travel around the sun in the early morning.

However, I now wonder if it is more likely for a massive, life-ending impact to occur around the equator than, say, at the North Pole.

Anyone have any insights? I already looked for this question on Google, and I only got some parts of the answer.

submitted by /u/occipixel_lobe
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Why is average income calculated as GDP ÷ Population and not GDP ÷ Working Population?

Posted: 06 Jan 2019 09:14 AM PST

Since we want to find the average income of the average worker, then why is average income calculated as GDP ÷ Population and not GDP ÷ Working Population?

submitted by /u/UniversallyUniqueID
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Why are the solar panels on ISS different from the ones usually seen here on earth?

Posted: 07 Jan 2019 04:44 AM PST

Does squid ink share any similarities to “real world” ink we use in our pens and printers? Or is it just a colloquialism?

Posted: 06 Jan 2019 07:49 PM PST

What determines whether something will burn or melt?

Posted: 06 Jan 2019 05:25 PM PST

Why is my current cold "a cold in the nose", whilst others are "in the head/chest/throat"? Is the infection localised there, or is it that different cold viruses exhibit different symptoms?

Posted: 06 Jan 2019 09:40 AM PST

Hipparchus is credited with discovering the precession of the equinoxes; but how can you measure such a slow process, especially in ancient Greece?

Posted: 06 Jan 2019 03:11 PM PST

Why are albino rats used in scientific research?

Posted: 06 Jan 2019 02:52 PM PST

I was reading into the Rat Utopia studies and it mentioned that albino rats were used in most of the studies, which got me wondering:Why are albino rats used in scientific research?

What are the benefits and drawbacks?

Are albino rats the most common rat used in research and if so why?

submitted by /u/SReject
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What specifically about cigarettes raises hematocrit levels?

Posted: 06 Jan 2019 06:34 PM PST

Is it the nicotine they contain or is it something else, or a combination of these answers?

Essentially, would vaping or using nicotine patches/gum/other nicotine-delivering smoking cessation aids effect (raise or sustain at higher than ideal levels) someone's hematocrit/hemoglobin levels in the same manner as smoking tobacco?

submitted by /u/cartooneye
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How are the repeated segments in a centipede developed?

Posted: 06 Jan 2019 12:46 PM PST

What is a Lagrange point? What happens there?

Posted: 06 Jan 2019 01:06 PM PST

how do different parts of the crystal know to stop growing at the right point to give it a "regular" shape?

Posted: 06 Jan 2019 12:00 PM PST

My understanding is that when a cubic crystal shape forms, that usually (always?) means that the underlying molecular structure is a cubic crystal lattice (or, at least, cuboidal), where the structure can be created by placing atoms in some pattern inside a cuboid and then repeating that cuboid in all three dimensions.

But I never understood what forces would cause a crystal to grow in a shape that mimics the building block of the lattice. In other words, suppose atom X is somewhere on the face of one of the crystals. The crystal stopped growing (in the direction orthogonal to the face of the crystal) exactly at atom X. 5,000 molecules down from atom X is atom Y, and the crystal also stopped growing in that direction at atom Y. What forces would cause the growth to be "coordinated" in a way that it stopped growing in that direction at both atom X and Y and all of the atoms in between? (And similarly for all the atoms on the edge between two faces of the crystal, where the crystal stopped growing in *two* directions at all of those points?)

submitted by /u/bennetthaselton
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Is a figure 8 solar system possible?

Posted: 06 Jan 2019 09:18 AM PST

I was wondering if it is possible for a solar system to exist where there are two suns that are essentially identical and a decent distance from each other so that the planet(s) are able to pass between them at one point in their orbit. Creating a system where the planet(s) are revolving around one star, get caught in the middle, and then latch onto the other star and start revolving around that one, starting the cycle over again.

submitted by /u/candle_burner
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Is there any way to effectively convert brain waves into energy?

Posted: 06 Jan 2019 01:25 PM PST

I've seen several articles in my few minutes of research over this that show people using their brains to power a small light bulb.

I also read an excerpt from MIT that claims that brain waves are about a billionth of the strength of the Earth's magnetic field.

submitted by /u/officialbryson
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What makes/ how does the earth spin?

Posted: 06 Jan 2019 08:51 PM PST

Like what makes it spin, I know it revolves around the sun because of gravity (I could be wrong if so correct me) but what makes it spin!

submitted by /u/wagagaw
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Is there a genetic link between cleft palate and torus palatinus?

Posted: 06 Jan 2019 09:19 AM PST

I (28F) have a torus palatinus on the roof of my mouth, which is just a harmless bony growth that sticks out. My brother (27M) was born with a cleft of the soft palate. So basically, I was born with an excess of bone and he didn't have enough. I'm wondering if there is a reason we would both have palate abnormalities, since there is no other family history of it, and I haven't been able to find an answer through my own research.

submitted by /u/maineiacmama
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Why is it apparently impossible to create a velocity profile for fluids with turbulent flow, but not laminar?

Posted: 06 Jan 2019 12:16 PM PST

Why do Jupiter's moons never colide?

Posted: 06 Jan 2019 07:44 AM PST

I mean, shouldn't the gravitational force between each other be enough to attract themselves when they pass by?

submitted by /u/scrytor
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We always hear about possible large meteors hitting the earth, but what about the moon?

Posted: 06 Jan 2019 10:04 AM PST

Would there be effects to us from debris if it was a big enough meteor? How likely is it we'd see a meteor strike on the moon?

submitted by /u/Vectorman1989
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Why weren't dinosaurs discovered till the mid 1800's? With civilizations being around for 5,000 years you would think that they would have been discovered earlier.

Posted: 06 Jan 2019 07:49 AM PST

Is there a general rule or way to determine whether a compound is soluble or less soluble?

Posted: 06 Jan 2019 01:35 PM PST

Hello,

Like the title says, is there any way to determine just by looking at the formula how soluble a compound is? Thanks.

submitted by /u/ComradeFlorr
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Sunday, January 6, 2019

What caused the growing whining sound when old propeller planes went into a nose dive?

What caused the growing whining sound when old propeller planes went into a nose dive?


What caused the growing whining sound when old propeller planes went into a nose dive?

Posted: 05 Jan 2019 08:31 AM PST

I'm assuming it has to do with friction somewhere, as the whine gets higher pitched as the plane picks up speed, but I'm not sure where.

Edit: Wow, the replies on here are really fantastic, thank you guys!

TIL: the iconic "dive-bomber diving" sound we all know is actually the sound of a WWII German Ju87 Stuka Dive Bomber. It was the sound of a siren placed on the plane's gear legs and was meant to instil fear and hopefully make the enemy scatter instead of shooting back.

Here's some archive footage - thank you u/BooleanRadley for the link and info

Turns out we associate the sound with any old-school dive-bombers because of Hollywood. This kind of makes me think of how we associate the sound of Red Tailed Hawks screeching and calling with the sound of Bald Eagles (they actually sound like this) thanks to Hollywood.

Thank you u/Ringosis, u/KiwiDaNinja, u/BooleanRadley, u/harlottesometimes and everyone else for the great responses!

Edit 2: Also check out u/harlottesometimes and u/unevensteam's replies for more info!

u/harlottesometimes's reply

u/unevensteam's reply

Edit 3: The same idea was also used for bombs. Thank you u/Oznog99 for the link!

submitted by /u/osirisfrost42
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How does heat transfer between a solid to a liquid?

Posted: 06 Jan 2019 06:39 AM PST

So, I understand the process is called convection (right?), and I understand how convection works, but I'm curious about what is happening on the molecular level. If I understand it correctly, the molecules of a substance move (or vibrate or something like that) at different speeds depending on their relative heat. Hotter things move/vibrate faster, cooler things move/vibrate slower, and solids are so cold that their molecules are hardly moving at all, so the entire substance is locked up in the form of a solid. I know this is super simplified and probably full of over generalizations, but I just want to lay down the concept first.

Now we come to the root of my question: Lets imagine a glass of cold water, sitting on the table. For the sake of my poor analogy, lets forget about the part where the air touches the water (say the glass has a lid on or something). Now, the water will gradually increase to room temperature through convection. Here's the bit I don't understand. On the molecular level, the glass will have to heat up first. The heat in the air will warm the glass, which will warm the water in the glass. But the glass is a solid, and will remain so at very high temperatures. So its molecules would be moving very slowly, right? Slower than the molecules of the liquid water, right? But the glass is warmer than the water, because it has a higher melting point, and therefor transfers heat to the water. So how do slower moving/vibrating molecules transfer their greater heat/energy to faster moving/vibrating molecules?

If this belongs on a different subreddit, please let me know.

submitted by /u/Krazy-Kat15
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Has global warming had any noticeable changes in animal migration patterns?

Posted: 05 Jan 2019 03:37 PM PST

Is it ever possible to move at a negative speed?

Posted: 06 Jan 2019 05:56 AM PST

Would this always be classed as some form of 'reversing' or would moving back in time be classed as a negative speed? Or is there simply no such thing and it's always a positive speed?

submitted by /u/WeNeedCheaperPastry
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Is a Mach 3 sonic boom louder than a Mach 1.5 sonic boom? Would travelling super sonic for longer periods of time increase the loudness or intensity of the boom?

Posted: 05 Jan 2019 10:44 AM PST

If I understand correctly - The waves essentially cannot get out of the way quick enough when travelling supersonic and they get all bunched up. So, i have been curious to find out if speed and duration have an effect on the intensity of the sonic boom.

submitted by /u/4fingertakedown
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Experimental fusion rectors on earth require temperatures hotter than the sun. Since the sun has the process of fusion at 15million degrees, why do we need higher temperatures than the sun to achieve it?

Posted: 05 Jan 2019 04:45 PM PST

How does turning on AC with heat actually help to defog a car windshield?

Posted: 05 Jan 2019 05:11 PM PST

From reading various tricks to help defog the car window, people recommend turning on the AC with high heat.

However if it's set to heat the car, doesn't it bypass the AC condenser and just pump hot air from the radiator without the benefit of condensation on the condenser coils?

submitted by /u/FmBeanie
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How does a plant know which way is up so that it can grow in that direction?

Posted: 05 Jan 2019 09:11 PM PST

What is laminar flow?

Posted: 05 Jan 2019 08:53 PM PST

Have u guys seen some pictures/videos of a seemingly steady stream of water flowing downwards, but when a guy touches it, it behaves like a normal water stream. How does that work?

Link: https://www.reddit.com/r/blackmagicfuckery/comments/acvvwy/laminar_flow/?st=JQKZPWRL&sh=04837908

submitted by /u/housemosq
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On a molecular level, what differentiates spring steel from regular steel?

Posted: 05 Jan 2019 08:49 PM PST

Why does the boiling point of water rise when you put salt in it?

Posted: 05 Jan 2019 09:57 AM PST

I understand that when you impurities in to a liquid like water that the boiling point would rise, but when you put salt into water, it dissolves and free ions roam through the water. Because of the free ions electricity can be conducted throughout the water. Shouldn't it be the case that because of the free movement of electrons, heat also conducts more easily in the liquid and as a result the boiling point would decrease?

submitted by /u/KidGIN
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What is the difference between a external and internal force?

Posted: 05 Jan 2019 08:28 PM PST

Why is compression a internal force? Can't it be a external force because gravity continuously compresses oneself?

submitted by /u/DrBublu
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Can you explain me the electroweak interaction in a simple way?

Posted: 05 Jan 2019 09:52 AM PST

Can one of you guys please explain me how does the electroweak interaction work and in which way do electromagnetic and weak force interact?

submitted by /u/azor_lor19
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Why do insulators have a large band gap?

Posted: 05 Jan 2019 06:45 PM PST

So I understand that insulators and conductors have a large bandgap, so you need to excite the electrons to move them to the conduction band to allow electricity to conduct, and I also understand that for metals, the valence and the conduction bands are continuous so that electrons can just go to the conduction band when positive and negative ends are established, but why is it that insulators have such a large band gap in the first place, whereas metals do not?

Appreciate any help!

submitted by /u/IsoLeucineLeucine
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What methods are there for solving the quantum many-body problem?

Posted: 05 Jan 2019 08:57 AM PST

If anything having mass has an equivalent amount of energy and vice versa, does heating up an object change its mass? How?

Posted: 05 Jan 2019 09:55 AM PST

The mass-energy equivalence states that anything having mass has an equivalent amount of energy and vice versa. If we have a mass of metal and we heat it by some x decrees Celsius then it's potential (correct definition?) energy increases. This is what I recall from my Physics classes. But how does heating up an object increase that object's mass? How does it lose mass as it cools?

submitted by /u/FirstHoratio
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If light, travelling from denser to rarer medium, is incident at an angle equal to the critical angle, it grazes the surface. However, a light traveling along the surface will not enter the medium from that same point. Is it a violation of the principle of reversibility?

Posted: 05 Jan 2019 08:28 AM PST

How does a turbojet reduce the intake's air velocity to subsonic speeds when aircraft it's powering is traveling at super sonic speeds?

Posted: 05 Jan 2019 10:03 AM PST

I'm trying to get a better understanding of turbojets, and one thing I've seen mentioned is that the air speed inside the engine has to be below the speed of sound. Why does the intake air speed have to be subsonic and how is it slowed? Does a ramjet accomplish slowing the air using the same principal? And what allows a scramjet to work with the intake air being super sonic?

submitted by /u/_meshy
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How are there only 7 orbitals for the “f” shape of electrons?

Posted: 05 Jan 2019 10:23 AM PST

When subdividing the periodic table into sections for the orbital shapes s, p, d, and f, you can see that there are 15 elements horizontally in the "f section". However every shape must have two electrons in each orbital, but 15 is not evenly divisible by two (and to my knowledge you can't have a half-orbital). What is the cause of this, or how can it be explained?

submitted by /u/DubiousBlue
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Saturday, January 5, 2019

Askscience special thread - Panelists, what are you working on?

Askscience special thread - Panelists, what are you working on?


Askscience special thread - Panelists, what are you working on?

Posted: 04 Jan 2019 10:25 AM PST

Some the older members of r/askscience might remember this thread from a few years ago where we asked panelists of r/askscience to describe their research.

The idea to get our flaired users to post a brief description of one of their current projects. Hopefully this serves to foster some more detailed discussion about your specialties!

submitted by /u/AskScienceModerator
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How come when you’re burned you’re not supposed to immediately put it in cold water? How does that hurt you more than help you?

Posted: 04 Jan 2019 07:33 PM PST

Are people who were conceived using fertility treatment more likely to be infertile?

Posted: 04 Jan 2019 05:53 PM PST

How does the spectrum of electromagnetic radiation emitted by an object change as the object's temperature changes?

Posted: 05 Jan 2019 07:06 AM PST

I know very little about science, but I spent part of the summer trying to learn about electromagnetic radiation. Then I took a long break. Now I'm trying to organize my notes, which are in disarray, and I want to make sure that I get everything essentially accurate.

I know that thermal energy contained within an object will be released in the form of electromagnetic radiation. And I know that as the temperature of an object increases, the spectrum of wavelengths emitted by that object will also change. But I'm not completely sure what the relationship is between temperature and emitted wavelengths.

I assume that hotter objects will release more high-energy wavelengths than colder objects - so for example, if Object X and Object Y are made out the same material, and Object X releases ultraviolet radiation, while Object Y doesn't release anything with a higher energy level than infrared, then I would assume that Object X is hotter than Object Y. Would that be an accurate assumption on my part?

submitted by /u/JFox93
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Looking at stars on a clear night, why do they seem to be gently flickering?

Posted: 04 Jan 2019 08:45 PM PST

Does your eyesight actually get worse if you read in the dark for extended periods of time or often do so? Why or why not?

Posted: 04 Jan 2019 03:13 PM PST

Do droughts have a specific cause that prevents rainfall for an extended period of time or are they a statistical anomaly of rainfall not occurring for an extended period of time?

Posted: 04 Jan 2019 08:18 PM PST

When neutron stars collide do they immediately form a black hole or would the collision produce ejecta?

Posted: 04 Jan 2019 04:48 PM PST

What prevents seeds from sprouting inside of ripening fruit?

Posted: 04 Jan 2019 04:53 PM PST

How can NSAIDs increase the risk of heart attack, yet aspirin therapy reduces it?

Posted: 04 Jan 2019 08:38 PM PST

When touching very hot water, why does it sometimes take a split second to finally realize how hot the water actually is?

Posted: 04 Jan 2019 02:44 PM PST

What is the difference in the types microscopic life/bacteria/viruses present in a city/forest/open ocean?

Posted: 04 Jan 2019 05:26 PM PST

Why don't Orcas get large, creepy external parasites?

Posted: 04 Jan 2019 11:42 AM PST

I imagine they have some, but why not barnacles/whale lice (don't Google this within an hour of eating.)

submitted by /u/GretaTheBeeotch
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How do Saturn rings affect sunlight on its surface?

Posted: 04 Jan 2019 04:53 PM PST

Does Saturn have a perpetual night zone where its rings cast shadow or is there a short darkness period every day on each spot of its surface (if we could say that it has one)?

submitted by /u/mgtaboada
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Plant scientists, do you know of any plants whose trichomes (hairs on plants) move intentionally/functionally? What is the function or purpose of their movement?

Posted: 04 Jan 2019 04:58 PM PST

How does Bluetooth work?

Posted: 04 Jan 2019 01:22 PM PST

Why is there a minimum speed to leave Earth. Why couldn't you theoretically just walk up a large staircase if you had the equipment?

Posted: 04 Jan 2019 06:15 PM PST

Obligatory apologies for being on mobile.

Like if a staircase into space existed, why would that be impossible to walk up if you had a space suit? Is it the pull of gravity that gets more intense the farther you go? I hope I asked this the right way.

submitted by /u/AMiniMinotaur
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From the view of a chemist, why is lead so bad for humans?

Posted: 04 Jan 2019 04:02 PM PST

I am a new high school Chem teacher and am interested in exploring the Flint Michigan issues with my class from the standpoint of a Chemist. Is there a chemical reaction that we could discuss that would explain why Pb so bad?

submitted by /u/pinhead7676
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How is allele dominant to another at a fundamental, chemical level?

Posted: 04 Jan 2019 08:24 AM PST

I'm a senior in college graduating with a degree in chemistry and have always been curious about gene expression at a chemical level. Like say height or eye color, what chemical force in DNA/RNA/organelles/whatever is causing a gene to be expressed more than another or make the allele/gene "dominant"?

submitted by /u/Negromotor
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How do serotonergic hallucinogens(LSD, Psilocin, DMT) increase brain interconnectivity?

Posted: 04 Jan 2019 09:29 AM PST

Obviously it's not literally rearranging neurons. That would probably be really destructive to the brain.

submitted by /u/JuxtaTerrestrial
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Do we lose intelligence, or get slower to learn new material / skills, as we age?

Posted: 04 Jan 2019 05:42 AM PST

...I'm 27 and am half-convinced I can notice this already, compared to when I was in my early twenties. I'd like to know if this is true, and what sort of rate this decline will continue to happen at?

submitted by /u/HouseDownTheStreet
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Can pheromones repel animals from each other as well as they attract animals to each other?

Posted: 04 Jan 2019 02:33 PM PST

More specifically, I was thinking about how humans are drawn to each other to mate/love by pheromones - but on the other hand, can pheromones cause humans to kill/hate each other? Just curious. Thanks!

submitted by /u/rexallia
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