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Friday, February 5, 2016

With a heavy vehicle trying to stop on snow, what is the relationship between the higher mass increasing traction on the snow, but also increasing the momentum that has to be stopped?

With a heavy vehicle trying to stop on snow, what is the relationship between the higher mass increasing traction on the snow, but also increasing the momentum that has to be stopped?

With a heavy vehicle trying to stop on snow, what is the relationship between the higher mass increasing traction on the snow, but also increasing the momentum that has to be stopped?

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I often see pickups loaded with snow for traction, but it seems like extra weight might work against you at a certain point

submitted by /u/Rxef3RxeX92QCNZ
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Would it be more fuel efficient and less dangerous to float a rocket into the upper atmosphere with balloons before igniting the boosters?

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Can we construct regular polyhedra of arbitrary number of faces?

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It is known that there are only five regular polyhedra in 3D. I was wondering what would happen if one constrains an arbitrary number of repulsive points to the surface of a sphere. Would they find a steady state?

submitted by /u/caracatrepa
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If the ratio of matter to antimatter during the Big Bang was the opposite (1 billion matter particles to 1 billion and 1 antimatter particles) then is there any reason that we wouldn't have a universe made out of antimatter?

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Saw a video about matter and antimatter by Minute Physics and got me thinking.

submitted by /u/cornpownow
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Plasma: how can the same phase of matter seem so eclectic in its behaviour?

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Are different types of plasma as uniquely behaved as they seem, or is their apparent broad categorization justified? I don't know if this question is naïve, and I am a layman. Lightning, stellar surfaces, fire, aurora, etc. are all categorized as types of plasma, or at least partially so, but behave and appear quite differently. Does this mean that the phase is just a general term for ionized energetic gases, or that they're more similar than they seem to the untrained eye, with concise explanations for the different behaviours?

For instance, why doesn't lightning ever follow the convection rules of how fire spreads, or why doesn't fire get conducted into bolts? Shouldn't all plasma transfer energy similarly?

The question stems from other phases: liquids and other phases have recognizable and consistent patterns of behaviours. Plasma seems to be more indie.

Sorry for the long post. It feels like I'm just missing one or two simple pieces to make sense of it. Searching the Web just led to overcomplicated papers or TV sales.

submitted by /u/chefpadrino
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If there's no such thing as a perpetual motion machine, what keeps electrons constantly on the move and what causes light to "speed back up" when it moves through air and then water and then back into air?

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Glass: Liquid, Solid, or Something Else?

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After reading a fair bit on what state of matter room temp glass is, I have concluded that I don't know what to think. So, can anyone give me a definitive answer of whether or not glass is a liquid or solid?

submitted by /u/MooseWolf2000
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Why are radio frequencies split into radio waves and microwaves?

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I'm doing a project for school on radio frequency and how it is used for communication. However, it has been extremely hard to find any information on why it is split into radio waves and microwaves.

submitted by /u/Ploggy
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How much money (USD) is one electron worth?

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Very broad question, but I started thinking about this while reading about rooftop solar panels, and selling energy back to providers. So lets assume this context for the question.

I would guess the value of one electron in the energy grid is a decimal, followed by many zeroes before the first nonzero digit. However, I'm really not sure how one would calculate that. So, how would you calculate this, and what would you estimate the value to be?

submitted by /u/Valiant4Funk
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What is "unity" when referring to nuclear fusion?

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If consciousness is the information stored in the brain, could the information be altered such that the same brain becomes a completely different person/consciousness?

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Do prime numbers cease to exist at some point on the number line?

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I know there is a largest known prime number, but theoretically, will there be no more prime numbers past a point?

submitted by /u/Jean_Valjean_Valjean
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When you connect a voltage to a wire, how long will it take for it to be observable on the other end of the wire? Does the voltage propgate via electrons at the speed of light? Or is it slower?

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Does a black hole generate a magnetic field?

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How do 2 particles get entangled?

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i've been watching videos and reading up about a bunch of cosmology and quantum physics stuff and am trying to wrap my head around entanglement. i understand for 2 particles that are entangled, when you measure the spin (or other quantum characteristic) on one you instantaneously know what the spin on the other is, regardless of their separation. I watched a video where they showed a process of measuring entangled photons by splitting a diagonally propagating laser beam with polarizers, so that when two photons split, and they measure the polarization of one of the photons, they knew the other. but how/when are particles entangled? do you only get entanglement when a particle splits somehow, or can two nearby electrons be entangled somehow?

TL;DR does entanglement only happen when 2 particles are created together and are somehow linked, or can 2 non entangled particles somehow become entangled? if so, how?

submitted by /u/forrScience
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If hydrogen and oxygen are highly explosive when combined, then why isn't water, or at least steam, explosive?

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How many dimensions in the universe are expanding ?

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The observances of red shifts of galaxies eventually led to the proof that the universe is expanding.

Hubble's expansion law states that H=v/d (where H: Hubble's constant, v:galaxy's radial outward velocity (referenced from Earth), d:the galaxy's distance from earth).

Velocity here is a vector in 3D.

I was thinking about this was wondering that since the expanding universe is a true physical phenomenon, then what are the answers to the following questions:

(1) How can expanding universe phenomenon be interpreted and understood in terms of space-time rather than a classical space and time as separate ? I am really having a hard time wrapping my head around the application of space-time idea to the "expanding universe phenomena".

(2) What about looking and explaining this phenomenon in terms of M-theory's premise , that there are 11 dimensions. How many of those dimensions are expanding and what is happening to the other dimensions ?

Or am I asking the wrong question ? Because honestly, I am not sure that the dimensions M-theory talks about is a superset of the 3Space and 1Time dimension that we experience and are familiar with. Here, obviously I have assumed that it does.

submitted by /u/creepingdeathv2
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If you put a helium balloon in space. Which way would it float?

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Why is protein an information sink?

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What effects does the ambient temperature have on the combustion process (fire starting)?

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Starting a fire in the winter is more difficult than the summer. I understand that heat is a contributing factor to starting a fire, so it makes sense that more energy would be required in order to get the initial reaction. So, how cold would it have to be before starting a fire is impossible?

Would warming the fuel source make it easier?

I plan to do some tests but living in Georgia right now makes it difficult to find anything cold enough without cleaning out my freezer.

submitted by /u/wheresmycoffee
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When sound is loud enough to be damaging to your hearing, at what rate do you damage your hair cells?

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At 140 decibel damage occurs immediately. So say I'm in a room with 140 db loud noise without hearing protection for five minutes, how many hair cells did I lose when I come out again? And how did it impact my hearing range?

submitted by /u/HuubKe161
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How do rockets burn in space if there is no oxygen?

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What is happening in terms of Quantum Field Theory when matter and anti-matter interact? Is it like destructive interference between wavefunctions, analogous to classical wave interference?

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Thursday, February 4, 2016

Let's say I put a steel beam 1000 feet in the air above the earth, and this beam goes all the way around the world until it comes back and connects with it's original point, making a perfect circle. Assuming there is no support structure, would this steel beam levitate above the earth?

Let's say I put a steel beam 1000 feet in the air above the earth, and this beam goes all the way around the world until it comes back and connects with it's original point, making a perfect circle. Assuming there is no support structure, would this steel beam levitate above the earth?

Let's say I put a steel beam 1000 feet in the air above the earth, and this beam goes all the way around the world until it comes back and connects with it's original point, making a perfect circle. Assuming there is no support structure, would this steel beam levitate above the earth?

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Hopefully this is the right sub for this!

submitted by /u/Shit_man_idk
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The Hydrogen plasma produced in the wendelstein 7x experiment, will it still be hydrogen when cooled down?

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What effect would the heat death of the universe have on black holes?

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How can we can have motion relative to the CMB if it is observed from all directions?

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I just got put in my place by trying to call bullshit on someone who was saying we can measure our velocity relative to the cosmic microwave background. Apparently this is an actual thing. Can someone explain this please? How can the CMB rest frame exist if CMB photons are observed from all directions?

submitted by /u/nhingy
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What would happen if the superheated material inside a fusion reactor was exposed?

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What would the possible damage, if any, be?

submitted by /u/HeIIen
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Can accelerating spacetime expansion eventually rip apart a black hole?

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Space time is expanding and we know the speed of its expansion is accelerating. This pulls everything in the universe apart, though below the high-macro level this is effectively unnoticeable with almost no influence on bodies.

However, if this acceleration remains then inevitably (after many years) the expansion of spacetime will 'pull' on molecular/atomic bonds and break up bodies, right? The forces holding matter together won't be able to resist the incredible growth of spacetime pulling everything apart.

So I guess the real question is this: is there an upper threshold to the physical integrity of a black hole? Nothing physical can 'break apart' a black hole because obviously it would just be swallowed, but what about spacetime itself pulling it apart?

I want to speculate the answer is no, but obviously I'm not sure. Anyone have any comments on this?

submitted by /u/NEREVAR117
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Is it possible to have an orbit that doesn't bisect the planet?

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An orbit around just the middle of the northern hemisphere.

Most satellites I see appear to go right around the "middle" of the planet. I figure that is just because it is easiest, but is it the only realistically possible way to have an orbit without continuous adjustments.

submitted by /u/th3d3k0y
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Is there a specific volume a dangling water droplet has to exceed before it falls? Does the volume vary depending on the material or shape of the surface?

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Do mild seasons affect temporal patterns of hibernating and migratory organisms?

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The title says it all. I live in the South East U.S. and so far we have had a pretty mild winter.

submitted by /u/jluvin
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How much longer does it take 2 (electrically neutral) masses to reach eachother gravitationally when they travel parallel at equal relativistic speeds?

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For example, at v/c=0, the time it takes for two 1[kg] spheres at R = 2[m] would be about 271392[s]. Now I would expect that the time would double (for the non-moving observer) when the relativistic gamma factor is 2 (v/c = 0.866), but I can't find a clear reference where this is stated/explained.

submitted by /u/NoIslandsInSpace
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Could we create a metric time system that would work similar to days and years?

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A joke on The Simpsons talks about how the geniuses in Springfield got the trains running so efficiently that they even run on metric time. Is something like that possible?

submitted by /u/watusa
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If we have antennas that can transmit EM radiation in any frequency we can think of, would it be possible to create an antenna that transmits EM in the visible light frequency range?

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Why is IV tPA for stroke patients have to be administered (generally) in under 3 hours? Why wouldn't it be as beneficial afterwards?

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I've been trying to google the answer, but I just keep finding the guidelines, not an answer to why. I also see intra-arterial tPA has a general guideline up to 6 hours adding to my confusion. I know it increases the chance of hemorrhage, but does it somehow increase the likelihood even more after the 3 hour window?

Any and all info is appreciated.

submitted by /u/ugly_monkey
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How easily is nicotine absorbed through the skin? Does different skin have different absorption rates? & does nicotine act differently when absorbed through your skin compared to inhaling it?

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How do I know what atomic mass is correct on the periodic table when different tables have different atomic mass for certain elements?

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I am home schooling my 8 year old son and would like to start teaching him the elements on the periodic table. I have made flash cards for all 118 elements on the periodic table including symbol, atomic number, element name and atomic mass however different periodic tables seem to have different atomic mass for certain elements. I have added the other name and symbol for the elements that are known by two names, like 112, Copernicium is also known as Ununbium, but am unsure as to which atomic mass I should attribute to the cards when I get different AM from different tables. Anyone able to tell me which table is most accurate? Thanks in advance.

submitted by /u/ScarletOnyx
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can you extract jacalin with water?

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i'm trying to make a research about green synthesis of silver nanoparticles and there are some things i don't understand. one of it is that, i'm considering seed extract of a certain plant as the reducing agent of silver nitrate. this one study says that the jacalin content of the seed extract might have synergisitic effect with the silver nanoparticles that they've synthesized. but if you look at their extraction procedure, they only used distilled water to make seed extract. I've looked up some studies and they all say that they soaked the powdered seed and centrifuged it then used the supernatant for the experiment. i do understand that you can extract the chemical components that acts as antioxidants but here's the question, can you extract jacalin with just distilled water? a polar solvent? thanks in advance

submitted by /u/kuroandshiro
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Is there a name for a distribution given by y = (x-1)/(x+1)?

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How would I go about finding the limit of (1/x)^x as x approaches 0?

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So my friend and I have been arguing over this recent BC Calc test question and we can't seem to figure it out. He thinks that the answer was 1 because (1/0)x = ∞0 = 1, but I'm pretty sure that this is incorrect because the x0 = 1 rule only applies to constants. I thought that the answer was DNE because the limit from the right (1) ≠ the limit from the left (a nonreal number). Could someone please explain how one would solve this problem?

submitted by /u/IHaveDrainBamage
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Why do some quantities in physics calculations (electricity for example) take on complex values?

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College student here. I stumbled upon equations in physics on my own that take complex valued quantities. My question is: how can something like electrical impedance or current take on a complex value?

submitted by /u/PhantomWings
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Wednesday, February 3, 2016

What is the biochemical process in seeds that keeps track of cold temperature so that seeds germinate at the correct time?

What is the biochemical process in seeds that keeps track of cold temperature so that seeds germinate at the correct time?

What is the biochemical process in seeds that keeps track of cold temperature so that seeds germinate at the correct time?

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Many seeds require a period of cold (stratification) before germinating. How does the seed know that enough time below a certain temperature has passed before germinating? Obviously I realize that temperatures rise in the spring triggering germination but when people are trying to grow seeds they'll put them in the fridge for a certain period of time. The seeds will only germinate after they have spent that minimum amount of time in the cold. Removing the seeds early won't cause germination despite the fact that they went through a cold period.

submitted by /u/noodledoodle3
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Does the fetus absorb hormones such as cortisol or endorphins from the mother? Does the baby gets dependent and expects to receive it after birth?

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For example, if the mother is happy and cheerful throughout the pregnancy and releases fluxes of endorphins, does the baby absorbs it as fetus, and expects the flux of endorphins after birth?
Can lack of hormones be a reason for unrest in a baby - until they get 'rehabilitate'?

submitted by /u/am_i_here
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If you could use super slomotion camera that could see light move, what would you see, sitting in a room when you flipped the light switch off? A washing over of darkness, emanating from the light source- or just sudden darkness?

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Since E=mc^2, does a photon create a gravitational field ?

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Is a Single Measurement Precise?

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I just got back my science midterm and one of the questions I got wrong was bothering me. This was the question (not word for word of course, but same idea).

The actual mass of object A is 56.8842 grams. Which of the following is the most accurate measurement of object A __? Which is the most precise __?

A) 55.937 grams B) 57 grams C) 56.299104324 grams

I wrote in B for being the most accurate (it's the closest to 56.8842).

However for the second part I simply wrote "none" because I remember learning that precision comes from having multiple consistent measurements, and we were being asked about a single measurement. I was confident that I caught a trick question, since my teacher has done trick questions on previous tests, but they marked me wrong. They said answer C was correct because precision comes from having the most significant digits.

Am I wrong? I feel like the way this question was asked is a bit confusing, so please explain in detail whether or not I'm missing something or outright wrong.

submitted by /u/OhMyPasta
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Why does the derivative of acrtan(x) look like the normal curve?

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I looked up the equation for the normal distribution and I can't see any connections between it and 1/(x2 +1). Are they related somehow? Or are they not really that similar and just mildly resemble each other? Thanks!

submitted by /u/icebergelishious
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When did we become aware that there is no life on Mars?

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Back on a time before the space exploration, we didn't really know very much about our neighbous in the solar system. So there was a time when the scientific community didn't really know how was the conditions in Mars (and, why not, Venus).

My question is: when did we learn that these places are sterile? How did the scientific community react? Where they expecting something else?

submitted by /u/alvesjnr
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Are newborns just 'blank slates'? In other words, can you train a newborn to grow up to be anything you want (a doctor, hitman, mathematician)?

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Can Galaxies "Die" and What Might it Look Like?

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Could someone please give a scenario in which the cardinality of an infinite set becomes important?

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Could someone describe for me a case in which it would be necessary to denote the cardinality of one infinity as opposed to that of another, and what branch of mathematics this falls under? I'm having trouble thinking of a practical example other than the ring of natural numbers compared to the set of real numbers.

submitted by /u/c3n3k
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Is there evidence of a moon orbiting a moon orbiting a planet?

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Has there ever been evidence of a smaller object orbiting the moon of a planet?

submitted by /u/Retardhunter
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If the edge of the observable universe is 46.5 billion light years away, why is the most distant object ever observed (EGSY8p7) only 13.2 billion light years away and still considered to be 13.2 billion years old?

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Edit: The answer is, it isn't. The figure of 13.2 billion light years is "light travel distance" not "actual distance". "Actual distance" to EGSY8p7, being the distance as a result of universal expansion, is approximately 30 billion light years.

Thanks /u/adamsolomon

submitted by /u/youreeka
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Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology

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Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Economics, Political Science, Linguistics, Anthropology

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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How can a black hole emit x-rays when its gravity is so strong that even light cannot escape?

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What would happen if you frayed the ends of hundreds of small wires connected to two ends of a battery, and brushed them together?

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Would it be possible to use GFP to create glow in the dark tattoo ink?

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Why is it that some craters, notably on the moon, have a small elevation in the centre/point of impact?

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i've read that the central uplifts are due to gravity but I don't understand the role of gravity there.

submitted by /u/Legal_loophole
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Why is nitrogenase not used in industrial production of fertilizer?

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I was curious if there is a specific reason that we have not made a genetically modified organism that could secretes or at least produces nitrogenase. Is it more complicated, why is this not a practical why to produce fertilizer? Is this currently being researched?

submitted by /u/CausticCatalyst
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This reasoning shows that protons have no energy (or momentum). Where did I go wrong?

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Momentum is equal to the mass of an object*its velocity. A photon is massless, therefore it has no momentum. When you plug this into E2 = (pc)2 + (mc2)2, it would mean that photons contain 0+0=0 Joules of energy. Now, we all know that is far from the truth and that photons have both energy and momentum. So, where did my reasoning go wrong?

submitted by /u/MVP_Redditor
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Can the collision between two photons create two electrons?

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I have read that it can create an electron as long as the energy in the photons is bigger than the rest mass of an electron. Can we have photons whose energy is greater than the rest mass of two electrons?

submitted by /u/oTomas
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Is it possible to diffract bacterium?

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In a similar fashion to electron diffraction, is it possible to diffract bacterium?

submitted by /u/Branwolf
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