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Saturday, March 18, 2017

When a nuclear device detonates, the shockwave trends to clear overhead clouds, exposing the sky above. If it was raining, does that mean a nuclear device would stop the rain?

When a nuclear device detonates, the shockwave trends to clear overhead clouds, exposing the sky above. If it was raining, does that mean a nuclear device would stop the rain?


When a nuclear device detonates, the shockwave trends to clear overhead clouds, exposing the sky above. If it was raining, does that mean a nuclear device would stop the rain?

Posted: 18 Mar 2017 05:23 AM PDT

Is it possible to see the American flag on the moon via telescope?

Posted: 18 Mar 2017 05:53 AM PDT

Do gamma rays continue on down in size of wavelength to the Planck length or do they stop at some point, and if so, why?

Posted: 18 Mar 2017 06:26 AM PDT

Just trying to wrap my grape around the static nature of the speed of light and it's implications. Has it been postulated or shown, at some point, that electromagnetism and all things that propagate it exist on an, as yet not perceived dimension like the connection between matter and antimatter?

submitted by /u/Superstringcheese
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Why is the "philia" suffix being used increasingly by academics to denote sexual, or "eros," love, when the Greek roots are clear in their respective differences of meaning?

Posted: 17 Mar 2017 05:25 PM PDT

Does this mean that bibliophiles want to have sex with books, or audiophiles have orgasms listening to music? Doesn't the injudicious use of the suffix to denote sexual attraction in certain terms (paedophile, androphile, gynephile, et al.) lead to confusion and difficulty educating others? Shouldn't any "philia" that is defined as sexual in nature be renamed with the "-erotic" suffix, since the Greek roots are defined precisely?

submitted by /u/Paracortex
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What is the rate of formation for Uranium 235 in relation to Uranium 238 and how do we know?

Posted: 17 Mar 2017 02:32 PM PDT

In supernovae, where Uranium 235 and Uranium 238 are formed, how much Uranium 238 is formed in relation to Uranium 235? And More importantly, how do we know why this is the case?

As far as I know: When working out the age of the earth you have to know what the rate of formation are for the different nuclear isotopes so that you can use their different rate of decay to calculate the age of the earth.

submitted by /u/mmmmph_on_reddit
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Do photons absorb from, or lose energy to, other particles they hit? eg. If you heat a room, does that affect the light in the room?

Posted: 17 Mar 2017 11:04 PM PDT

How are some bacteria able to survive in the upper troposphere?

Posted: 17 Mar 2017 01:48 PM PDT

I read in this article that some bacteria can survive for weeks at an altitude of about 10 km. How can they withstand the low pressure and cold for extended periods of time? And how are they able to quickly readjust to sea level conditions once they land?

submitted by /u/HalfGondorian
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Would it be (theoretically) possible to use the heat in the air to generate electricity effectively enough that it would cool the air significantly?

Posted: 17 Mar 2017 02:15 PM PDT

The reason I'm asking is because if it was possible you could create an air conditioner that would generate electricity.

submitted by /u/qazmoqwerty
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At what point do foreign words from one language become officially adopted into another language?

Posted: 17 Mar 2017 01:29 PM PDT

It's very common for languages to adopt words from other languages, but at what point does it become official? For example, the German word schadenfreude, is used so much in English now, at what point would the English language officially adopt it as an English word with German roots, if ever?

Edit: Formatting

submitted by /u/qna1
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Why don't wireless chargers interfere with sensitive electronics like processors, sensors, and radios?

Posted: 17 Mar 2017 09:44 AM PDT

What causes the irregularities in the shape of the nuclear explosions in the recently declassified nuclear test videos?

Posted: 17 Mar 2017 06:04 PM PDT

These videos show some interesting nuclear explosions and I was wondering why the explosions are not more uniform and what's causing the parts of the explosion that protrude or seem to be moving faster than the bulk of the expansion.

submitted by /u/stanley_leverlock
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What is known about the general impact of climate (specifically average temperatures) on human health? Is it physically healthier to live in a hot place?

Posted: 17 Mar 2017 01:23 PM PDT

Think about two comparable people but one lives in Russia (doing outside work year-round) and one lives in Vietnam with no air conditioning.

Does long-term exposure to heat/cold noticeably change how our bodies work? Is there any research with conclusions like "people in hot countries metabolize fat quicker" or "people in cold countries have lower cancer risk"?

All I know is that it's probably hard to make comparisons with large groups of people because genes, diets, and healthcare in colder countries are different than tropical ones. Still, I'm wondering how much temperature matters.

I appreciate any insights you guys could share on this.

submitted by /u/H3H3472
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When was the equation of gravity first formulated?

Posted: 17 Mar 2017 03:29 PM PDT

I initially thought it was from Newton's Principia but I can't find any sort of page reference to an equation, only general thoughts on the inverse square relation between F and r.

submitted by /u/EliteTazer
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Why do we get stuffy/runny noses when we cry?

Posted: 17 Mar 2017 02:16 PM PDT

Will all the Lithium-ion batteries we keep in our attics ignite eventually?

Posted: 17 Mar 2017 12:10 PM PDT

Won't each one of them ignite as soon as their protective layer fails to keep the oxygen out? Or do they somehow "disarm" themselves over the years?

submitted by /u/okiclick
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Would the electromagnetic field diverge into its component fields at a low enough temperature or some conditions?

Posted: 17 Mar 2017 08:01 AM PDT

Why do particles that seem to be on the surface of the objective lens of a microscope come into focus when the stage is lowered far below the working distance?

Posted: 17 Mar 2017 06:44 AM PDT

I work in a clean room doing microfabrication work. I've noticed that when looking through a microscope, if you lower the stage very far, beyond the working distance of the tool, eventually a plane will come into focus where you can see stationary particles/debris (they don't move when the stage is moved laterally, so must be somewhere within the microscope - many I've asked agree this is likely a view of the surface of the objective lens).

Why do these particles come into focus? How does lowering the stage change the plane of focus to a point far above the stage, presumably on the objective lens, or even higher up in the optical pathway within the microscope? I've asked a number of the smart people in my lab but nobody can explain it.

submitted by /u/Iwantapetmonkey
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Why are some colours easier to see on a black background than a white, eg yellow?

Posted: 17 Mar 2017 10:04 AM PDT

This picture demonstrates what I mean. It's easier to see the yellow on the black background, and it's easier to see the purple on the white background.

Is the reason similar to why, when you print out a colour picture in monochrome, red and purple appear black whereas yellow appears white?

submitted by /u/Koquillon
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In special and general relativity, if the "light cone" visualization shows that the past light cone behaves like the future light cone in reverse, how is there light before it was lit at event E?

Posted: 17 Mar 2017 11:05 AM PDT

https://en.wikipedia.org/wiki/Light_cone shows a 2D graph where y-axis in (x, y, z) is replaced by time so the reader can visualize the concept easier. Although it is in fact easier to visualize the future light cone I'm having trouble understanding the concept of past light cone.

It is stated that the past light cone behaves like the future light cone in reverse, a circle which contracts in radius at the speed of light until it converges to a point at the exact position and time of the event E. In reality, there are three space dimensions, so the light would actually form an expanding or contracting sphere in three-dimensional (3D) space.

Let's imagine we light a candle and now there is light. If we rewind to a time before we lit the candle, there is no light. However, in spacetime, and according to the graph, there is and it contracts at the speed of light until it converges to the exact position and time of lighting the candle.

How is it possible that there exists light in some other plane that is undetectable to us, and the moment I light a candle it shows itself? And why is the past light cone considered to be future light cone in reverse?

submitted by /u/barnard33
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Is there a term in evolutionary biology for the opposite of 'koinophilia', where mate selection favors rare or distinctive rather than common phenotypes?

Posted: 17 Mar 2017 07:31 AM PDT

As an example, there was this study on guppies that showed that rarer male morphs had a sexual selection advantage over common morphs. Is this effect observed often enough to have its own name, or would it just be subsumed into the more general category of 'negative frequency dependent selection'?

submitted by /u/CalibanDrive
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Is the irregular shape of the periodic table caused by imperfect classification or just because that's how the universe is?

Posted: 17 Mar 2017 07:56 AM PDT

It just seems to me that the table should be a perfected organized shape instead of having hydrogen and helium alone at the top and then the Lanthanoids and Actinoids being shown oddly at the bottom

submitted by /u/YellowStopSign
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Friday, March 17, 2017

Could an iPod ever successfully shuffle an album in the correct order? What are the odds of this?

Could an iPod ever successfully shuffle an album in the correct order? What are the odds of this?


Could an iPod ever successfully shuffle an album in the correct order? What are the odds of this?

Posted: 17 Mar 2017 05:20 AM PDT

Why so many organic substances containing NO2 groups are explosive?

Posted: 16 Mar 2017 06:01 PM PDT

Is there a way for us to know what the population of any given species of dinosaur was during their time on earth? And if so, how?

Posted: 16 Mar 2017 04:32 PM PDT

Have there been any conjectures proven false, despite being widely believed to be true prior to the disproval?

Posted: 16 Mar 2017 11:42 AM PDT

Many famous conjectures (e.g. Goldbach's Conjecture) may not be formally proven, but are widely believed to be true due to strong heuristic and statistical evidence, and a disproval seems exceedingly unlikely.

Has there been a case where a conjecture, widely believed to be true for a long time, has actually been proven false later?

submitted by /u/GeneReddit123
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What would the creation of a black hole look like?

Posted: 17 Mar 2017 02:07 AM PDT

Can we pull a reflected image off a "nonreflective" surface?

Posted: 16 Mar 2017 12:42 PM PDT

Can we pull a reflected image off a "nonreflective" surface?

Reflectiveness is relative. A dirty mirror could be called reflective. A cracked or distorted mirror too. But how about white sheet of paper? Or a rock?

It may not be an image that our eye or mind can appreciate, but maybe we could run the reflected light through a noise filtering algorithm.

So I guess the real question is, how good are our reflected light image extraction algorithms? What's the limit on extractability?

submitted by /u/woodrail
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What does "m" in atomic mass number mean?

Posted: 16 Mar 2017 12:59 PM PDT

I sat down here reading and I don't seem to understand what "m" means in the ending of an atomic mass number. For an example the isotope 234m Protactinium. First of all what does it mean? And how would it affect decay?

submitted by /u/No-Yes-No
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Is there a theoretical maximum magnetic field strength?

Posted: 16 Mar 2017 06:12 PM PDT

I understand this may be expressed in terms of... what, volume of spacetime?

submitted by /u/askingyourmum
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Since the honeybee is an foreign species in North America, would it really be that bad for NA if all honeybees died out?

Posted: 16 Mar 2017 08:43 AM PDT

Since honeybees are technically an invasive species, would it have much impact? How did pollination work before bees in the Americas?

submitted by /u/pommefrits
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Quantized Momentum Uncertainty in the Particle-in-a-Box experiment?

Posted: 16 Mar 2017 08:56 PM PDT

Hello everyone. In regards to the particle-in-a-box experiment, we know that said particle can only exist at discrete wavelengths, and from the de Broglie theorem, discrete momenta as well. From this, you can also derive the discrete energy levels said particle can exist in, but my question is regarding the application of the uncertainty principle to this situation. Although our momenta can only be discrete, doesn't there exist uncertainty in the direction (i.e. left or right), and thus the uncertainty in the momenta is twice the discrete momentum? If this is true, then, my question is how exactly the momentum uncertainty can be discrete, since it seems it should be continuous. If this is false, then could someone please explain why it is? I feel like I'm making an incorrect assumption here, but I don't know where. Thanks!

submitted by /u/Quick_Question404
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How does 2,4-dinitrophenol span membranes?

Posted: 16 Mar 2017 04:35 PM PDT

In biochemistry, a question was raised that said 2,4-dinitrophenol distrupts the proton gradient created in mitochondria by acting as a proton transporting molecule. But how does it span a hydrophobic mitochondrial membrane if the molecule itself seems so polar?

submitted by /u/thathomelessguy
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In four (or three) fundamenal interactions, why only Electromagnetic force can be observed in the form of attract and repel force, while others are only attracting?

Posted: 16 Mar 2017 09:31 PM PDT

If we're trying to unite them in a unified field, why's there that difference?

submitted by /u/DogeoftheShibe
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Do logarithmic functions have to be base ten?

Posted: 16 Mar 2017 09:28 PM PDT

It seems like a lot of functions can be expressed logarithmically, such as that for sound. Is this just a coincidence that it goes along with our base 10 system or can it be expressed in any base?

submitted by /u/minnesotanationalist
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[Neurochemistry] How exactly does dopamine receptor downregulation cause the impulse to go get more drugs?

Posted: 16 Mar 2017 05:03 PM PDT

So I just finished listening to "The Addictive Brain" on the Great Courses and there was something I wanted to make sure I'm understanding right:

I get that with frequent use of something like cocaine, postsynaptic dopamine receptor availability decreases. However, how would this aid in the impulse to go out and seek the drug?

I understood from the course that for an addict, pleasure gained from the drug decreases with use and craving for the drug increases. And, environmental cues or triggers will convey to the addict that this is the familiar situation in which the behavior of buying drugs leads to a big reward, so dopamine rises in response to the trigger and the drug addict performs the drug purchasing behavior. However, if their dopamine receptors become more and more downregulated with drug use, wouldn't their impulse to purchase the drug be lessened because of this?

That is, the presynaptic dopamine release may get bigger due to stronger establishment of triggers (thanks to VTA), but because the postsynaptic dopamine receptor availability is decreasing, shouldn't the capacity to produce an effect (impulse) be lessened?

I'd really appreciate any clarification on this. Or, if what I've written above shows that I'm misunderstanding some mechanism please let me know

submitted by /u/batslicecameltruck
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Considering the fact, that bananas contain unstable radioactive isotopes of potassium, how many bananas would it take to give an average human radiation sickness ?

Posted: 16 Mar 2017 08:49 AM PDT

What is the Hellmann-Feynman Theorem?

Posted: 16 Mar 2017 07:34 PM PDT

Hi! I was recently suggested to read researches regarding the Hellmann-Feynman Theorem. As a result, I started with Wikipedia, as I assumed it would have the simplest version of it with clear explanations.

Nevertheless, despite reading the entry in Wikipedia, alongside a few research papers and lectures. I'm still a bit clueless regarding it.

Could anyone provide me a simple explanation of what the theorem states and how it is used in the applications mentioned in Wikipedia? Additionally, why must the eigenfunction be normalized and why must is be continuous with respect to the parameter of the Hamiltonian?

Thanks!

submitted by /u/B345tM0d3
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Does computer audio have something like a framerate?

Posted: 16 Mar 2017 10:41 AM PDT

I was using a Midi keyboard the other day and I noticed that there was a delay between pressing the keys and when the software played the notes (FL studio). When I went into the settings it said there was an intentional delay, and if I changed audio drivers it allowed me to lower it by a few milliseconds, but anything below around 30 ms delay would make the sound inaudible.

My immediate thought was how did they need delay when video games would make a noise instantly when you press a button. Is there some sort of "framerate" in computing that the audio needs to sync to?

submitted by /u/Njlamp
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Is there a critical age for someone's learning/development? [psychology]

Posted: 16 Mar 2017 09:27 AM PDT

Is there an age range where we learn the best? worst? Can't you learn at all ages?

submitted by /u/InsaneBaz
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Thursday, March 16, 2017

PSR J1748-2446ad is the fastest know pulsar at 716 revolutions per second, what is the limit of rev/s a neutron star can go through before tearing itself apart, and have we recorded any instances?

PSR J1748-2446ad is the fastest know pulsar at 716 revolutions per second, what is the limit of rev/s a neutron star can go through before tearing itself apart, and have we recorded any instances?


PSR J1748-2446ad is the fastest know pulsar at 716 revolutions per second, what is the limit of rev/s a neutron star can go through before tearing itself apart, and have we recorded any instances?

Posted: 15 Mar 2017 10:21 PM PDT

Also, does the size of a pulsar matter much when determining the break-apart speed?

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

Posted: 15 Mar 2017 08:04 AM PDT

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

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

Asking Questions:

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

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

Answering Questions:

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

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

Past AskAnythingWednesday posts can be found here.

Ask away!

submitted by /u/AutoModerator
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When there is an eclipse, why does the earth not become cold for that period?

Posted: 16 Mar 2017 05:08 AM PDT

Is the LHC beam visible to the naked eye?

Posted: 15 Mar 2017 08:10 AM PDT

If so, what would it look like? A bright, Science-Fictiony energy beam?

submitted by /u/PrequelMemeMaestro
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Why do even atomic-numbered elements (hydrogen neglected) seem more abundant?

Posted: 16 Mar 2017 03:43 AM PDT

In the solar system, neglecting hydrogen, 11 of the next 12 most abundant elements have an even number of protons--with nitrogen being the odd one out. And the bar graph from this page clearly shows a see-sawing pattern preferring even-proton elements as they get heavier. I've read about the Oddo-Harkins rule but it doesn't exactly explain the mechanism. Why is that?

submitted by /u/lordvadr
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What's under the desert?

Posted: 15 Mar 2017 11:14 AM PDT

If I were to get a fairly large vacuum cleaner and vacuum up all of the sand in the Sahara desert, what would I find underneath? Rock? Clay? Magma?

And how deep does the sand go anyway?

submitted by /u/PaulsRedditUsername
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Are there any big math discoveries still to be made?

Posted: 15 Mar 2017 09:35 AM PDT

Maybe I worded this wrong. But so many other sciences have big problems waiting to be solved. Physics for example is waiting for some grand unification theory. Biology has thousands of problems waiting to be solved. From cures to diseases to how did life begin.

So what about math? Have we pretty much figured it all out? Am I right to even try and compare it with other sciences in that regard?

Thanks to anyone who might take the time to answer.

submitted by /u/caper1144
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How fast can a nuclear powerplant shut down safely?

Posted: 15 Mar 2017 12:52 PM PDT

In a hypothetical scenario there is an impeding catastrophe that will affect the area of the plant. How fast can a nuclear power plant shut down so as to be safe and prevent radiation?
I am not asking to store away the nuclear waste and fuel in underground secure locations.
Just to make it safe and not worry about it for as long as possible.

submitted by /u/theofanhs
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If you walked in a straight line around a small asteroid long enough, would you eventually increase its spin enough to walk off into space?

Posted: 15 Mar 2017 01:59 PM PDT

Basically what I just asked.

submitted by /u/manufacture_reborn
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Is it possible to feel pain from strong ionizing radiation?

Posted: 15 Mar 2017 12:55 PM PDT

Not instant, but around 10 minutes after the exposure, experiencing joint/muscle aches? If there have been some instances where a subject "feels" pain after knowing he or she has been radiated, is it purely psychological?

submitted by /u/hawkiee552
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Is there a direct connection between the Uncertainty Principle and the Third Law of Thermodynamics?

Posted: 15 Mar 2017 09:09 AM PDT

I understand that Thermodynamics deals with entire systems. But in the single particle case, if it can never be cooled down to absolute zero, it will always have some vibration/motion. This seems very similar to the Quantum Physics idea that a particle only has a probability to be at a specific range [delta]x. Are these two versions of the same concept?

submitted by /u/mark0136
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What's the point of quantum teleportation, if you need to physically move an entangled particle to the desired end location? Couldn't you simply move the original particle instead?

Posted: 16 Mar 2017 04:00 AM PDT

I just watched minutephysics' video on quantum teleportation. One question I've always had it doesn't answer is: why bother? You need to physically move a bunch of matter to the location you want to teleport to, why not just move the thing you wanted there instead?

submitted by /u/MG2R
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Are the veins in a penis symmetrical?

Posted: 15 Mar 2017 04:25 PM PDT

Do rockets suffer from aerodynamic drag caused by truncated tail?

Posted: 15 Mar 2017 02:56 PM PDT

I don't know the right terminology so please let me explain.

In car and airplane aerodynamics, engineers have to consider not only aerodynamics on the front-facing side of the vehicle, but also on the back side. The idea is to reduce turbulence and low pressure, which has the effect of "pulling the vehicle back". I imagine this by having a moving object creating a vacuum (low pressure) behind itself, which "sucks in" everything around, including the object itself. Better shapes of the object will allow more air to fill out the vacuum (low pressure) area quicker, which will induce lower "pulling" force on the object.

Now the question is, what about rockets? If you look on this picture of the tail of Saturn V, it clearly shows how the rocket body is simply "cut off", or flat, and then the engine nozzles stick out. In my mind such moving body has to create lots of low-pressure-pulling force in the area between the flat rocket bottom and the tips of the nozzles, especially at high speeds.

Now obviously it cannot be perfectly aerodynamic as we may need some nozzle gimballing, or have the incoming air cool the nozzles down a bit, or simply vibrations prevent us covering up the engines/nozzles. But such a flat surface simply looks like a beginner's first attempt at rocket design (no offence :) ).

Or is that simply ignored due to short time spent in the dense part of the atmosphere?

submitted by /u/bremby
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Is proton beam radiation more effective than standard radiation for cancer treatment?

Posted: 15 Mar 2017 12:59 PM PDT

Do red shifted photons lose energy?

Posted: 15 Mar 2017 01:01 PM PDT

So say there are two hydrogen atoms in the same frame of reference in a vacuum- one in an excited state and one in ground state. The electron in the excited state drops to its ground state and releases a photon. The photon is absorbed by the electron in the other atom and it goes to an excited state.

What happens if they are not in the same frame of reference and the first hydrogen atom is moving away from the the second. Since the frequency of the photon is smaller when it reaches the second atom, is there enough energy to excite the electron? If not, where did the energy dissipate?

submitted by /u/banjoist
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[Math] How exactly is mass points used and when in a problem can you use it?

Posted: 15 Mar 2017 09:39 PM PDT

Additionally, when can you split a single point A up into points of mass A1 and A2 then later add them together? Can a point be split up into more then 2 points?

submitted by /u/AccountName77
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Does Moore's Law have a limit?

Posted: 15 Mar 2017 12:42 PM PDT

Does it predict an ever increasing doubling or is it bound to 'slow down' or even plateau at some point? Why?

submitted by /u/Velteau
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How would a compass act in space?

Posted: 14 Mar 2017 10:07 PM PDT

What would a magnet act like as you traveled away from earth? Would it continue to point towards the earth's pole or would other magnetic fields take over at some point?

submitted by /u/oceanceaser
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