Why is it that during the winter the static electricity in the air is greater? by PM_ME_YOUR_FAV_GUM in askscience

[–]AsAChemicalEngineer 4 points5 points  (0 children)

Depending on where you live, the air in the winter months can often be colder and drier. This makes air a better insulator so static charges are more able to "build up" before zapping you.

If the universe started from a singularity, and nothing can travel faster than light, then why can't we see the entire universe? by JimJimkerson in askscience

[–]AsAChemicalEngineer 16 points17 points  (0 children)

I suggest you check out the FAQ for a lot of this stuff:

But here's elaboration for your questions,

If the universe started from a singularity, and nothing can travel faster than light, then why can't we see the entire universe?

The big bang didn't happen at a single point of space, but in all of it. Rather think of it as a singular density that happened 13.7 billion years ago. The universe is either very large or even infinite in spatial extent. It is still true to say however that in the initial moments of the big bang, the observable universe (what we can see) was very tiny.

The universe can't expand faster than light

This actually isn't true, the universe's expansion can do whatever it wants including separating two galaxies (due only to expansion) at a recession speed which is greater than the speed of light. This isn't even an extreme edge case or anything as many galaxies are receding from us at faster than the speed of light. In fact all of them farther than 14 billion light-years away from us are doing just that--noting that the observable universe is about 46 billion light-years in radius. Some physicists won't call "recession velocity" a true velocity because it a) can exceed the speed of light and b) has nothing to do with the galaxies physically moving around. Both are at rest in relation to each other, but the distance between them simply grows which is a symptom of them living in curved spacetime.

If gravity propagates at the speed of light in a vacuum, and the speed of light through other mediums is lower than c... then can the speed at which gravity propagates also be slowed? by notasqlstar in askscience

[–]AsAChemicalEngineer 5 points6 points  (0 children)

Gravitational waves are self propagating waves of ripples in spacetime, much like light is a self propagating wave of ripples in the EM field. Just because you blocked the wave doesn't mean you don't feel sources on the other side.

In other words, you'll still feel the electric field caused by a charge or a gravitational field caused by a mass even if the medium is tuned to reflect waves of certain frequencies.

If gravity propagates at the speed of light in a vacuum, and the speed of light through other mediums is lower than c... then can the speed at which gravity propagates also be slowed? by notasqlstar in askscience

[–]AsAChemicalEngineer 14 points15 points  (0 children)

So gravitational waves can have an index of refraction much like light does in say glass or water. Therefore, a gravitational wave can be slowed in a medium much like light does as well as refract and reflect. The effect is incredibly tiny for any realistic situation though and has not been measured.

See: Ingraham, R. L. "Gravitational waves in matter." General Relativity and Gravitation 29.1 (1997)

The important difference is that EM waves interact with charge and gravitational waves interact with mass. This means whether a material acts like more of a metal (and thus opaque) or more like glass (and thus transparent) depends. While a rule of thumb everything is transparent to gravitational waves due to the strength of gravity, a medium which is naturally transparent to EM waves might be more opaque to gravitational waves then you'd otherwise expect and vice versa--again stressing the effect is tiny! This topic gets very complicated quickly and sadly there isn't much literature on the subject either.

If I put a lightbulb in a completely sealed box and turned it on, then off, where does the light go? by ArmedShadowfox in askscience

[–]AsAChemicalEngineer 0 points1 point  (0 children)

It gets eventually absorbed by the walls and converted into heat. Depending on the temperature of the box, the box will always be filled with some spectrum of light.

Does the Law of Conservation of Mass/Matter disprove the possibility of time travel? by Riptastic in askscience

[–]AsAChemicalEngineer 5 points6 points  (0 children)

What you've stated would be inline with other paradoxes caused by time travel. Almost all these paradoxes are basically caused by the same logical problem: In a sequence of related events ABC, time travel allows C-event to make B-event impossible even though C-event occurred after B-event. The grandfather paradox, tachyon gun and you coin example all fall into this.

What's actually preventing time travel is not just sickly logical outcomes, but more fundamentally that physics doesn't allow stuff like this to happen in principle. In this case the relevant physical law is that nothing can travel faster than the speed of light. Showing that FTL-travel is tantamount to time travel requires a bit of algebra to show. But to break it down as simply a possible: if there is a signal (say a telegram) that travels faster than light then there also exists a reference frame where it leaves and arrives at the same time as well as a frame where it arrives before it leaves.

3.0 Components Guide & Ship Upgrades by Squidofluvplays in starcitizen

[–]AsAChemicalEngineer 24 points25 points  (0 children)

Hey man, I think you should take a moment to meditate and then reread this string of comments again, because you're not going to come out being the good guy here. You and /u/STLYoungblood are both good content creators and a positive influence around the community, this isn't a "this town ain't big enough for the two of us" situation.

At worst this should have been handled politely through private messages and not aired out on the forums, but that's just my opinion.

What are some common (or uncommon) myths or misconceptions that people still believe? by bboyvad3r in AskReddit

[–]AsAChemicalEngineer 36 points37 points  (0 children)

It's worth pointing out that because glass doesn't have a 1st order phase transition, the boundary between solid and liquid is not clear cut like it is for water and ice. When you cool glass down, there simply is a point where we consider the flow to be negligible.

Death Stranding Necklace Equations Rundown by AbrasiveLore in DeathStranding

[–]AsAChemicalEngineer 1 point2 points  (0 children)

It's probably not referring to the triplet and singlet states, the H and V notation is most likely referencing horizontal and vertical polarization of photons.

Death Stranding Necklace Equations Rundown by AbrasiveLore in DeathStranding

[–]AsAChemicalEngineer 1 point2 points  (0 children)

The use of H and V is a bit curious then!

It's photon entanglement, the state is written using basis vectors |H> for horizontal polarization and |V> for vertical polarization. Basically, the equation is referencing the EPR paradox.

Death Stranding Necklace Equations Rundown by AbrasiveLore in DeathStranding

[–]AsAChemicalEngineer 2 points3 points  (0 children)

Nah, it's a bell state. For 2-qubits with maximal entanglement, there are four combinations to pick from.

Also what you've written uses ill notation. The subscript refers to the systems, generally "1" and "2" or "A" and "B" to refer to say a pair of atoms or photons or what-have-you, and therefore we can only have terms of the form |phi>_A|psi>_B.

If temperature is a metric for the average kinetic energy of particles, is there also a metric for the standard deviation of the kinetic energy of particles? by bastilam in askscience

[–]AsAChemicalEngineer 24 points25 points  (0 children)

Not quite right. The heat capacity of steam is nothing to write home about. It is comparable to the heat capacity of air, and it is much less than the heat capacity of liquid water.

The reason steam is more potent is that it has a strong latent heat of vaporization. It takes a ton of energy to boil water and if you condense steam on your skin, all that energy is dumped into your skin heating it up which can cause burning. This coupled with the abundance and inertness of water is why we use it in power plant turbine cycles. This high latent heat is due to the inter-molecular interaction of water molecules dipoles.

Steam also has the reputation of causing severe burns due to being often kept in industrial settings under very high pressure and temperatures such that if we replaced the steam with normal air, it'd still cause massive injury or death from exposure.

How able an object can burn you depends on three things,

  • Heat capacity (how much energy it can dump into you from cooling)

  • thermal conductivity (how quickly it can dump energy into you)

  • possible phase changes or chemical reactions

In this, only the last bullet point serves to make steam more able to burn you than just hot air.

Fellow US graduate students: the proposed Tax Cuts and Jobs Act would count your tuition waver as taxable income and likely make it impossible for you to live off your stipend. by JohnWColtrane in Physics

[–]AsAChemicalEngineer 1 point2 points  (0 children)

Is your tuition actually waived or is it paid behind the scenes by the powers that be?

I've been a TA and RA at my university my tuition is actually waived. The language used is "GA Remission" and in my university financial account records I have a dollar amount placed into my account every semester to exactly cancel out the tuition bill I receive. This transaction does not appear on my W2 nor 1099-T.

Doctor says I [30F] need to gain weight in order to get pregnant. My mom [53F] and husband [34M] are constantly nagging me to eat and I’m so annoyed. by UnapprehensiveCimex in relationships

[–]AsAChemicalEngineer 3 points4 points  (0 children)

For food convention, there is a distinction between an upper or lower case "c" in the word calorie.

1 Calorie = 1 kilocalorie = 1,000 calorie

A 600 kcal/hr (e.g 600 Cal/hr) rate for cardio exercise is not too crazy.

Just your average parenting goals by wizrares in iamverysmart

[–]AsAChemicalEngineer 1 point2 points  (0 children)

the Planck length is just where classical physics no longer applies

Really it's the length where our all modern physics no longer applies since we'd need to understand quantum gravity which we don't.

Just your average parenting goals by wizrares in iamverysmart

[–]AsAChemicalEngineer 2 points3 points  (0 children)

The Copenhagen interpretation of quantum mechanics is most likely to be correct

I'm not here to pedal any particular interpretation but Copenhagen has serious problems and is inconsistent with respect to the measurement apparatus / system divide. Wavefunction collapse also breaks unitarity and seems to just be a useful approximation if a quantum system interacts with a nearly classical system. To quote Steven Weinberg just a couple years ago,

"My own conclusion is that today there is no interpretation of quantum mechanics that does not have serious flaws. This view is not universally shared. Indeed, many physicists are satisfied with their own interpretation of quantum mechanics. But different physicists are satisfied with different interpretations. In my view, we ought to take seriously the possibility of finding some more satisfactory other theory, to which quantum mechanics is only a good approximation."

The newest missile launch by North Korea says it reached an apogee of 478 miles. How? by Aplasmabanana in askscience

[–]AsAChemicalEngineer 3 points4 points  (0 children)

Yup, the ballistic missiles really are going that high. Here's an explanation of North Korea's missile program from the Washington Post that I found particularly informative:

The basic idea is during testing they wanted the missiles to land close by (at least in the testing they usually do). They did this to either avoid antagonizing other countries by landing missiles near them in the Sea of Japan or to obfuscate the real low angle launch behavior of their missiles from prying international eyes. Presumably they understood the relationship between their high angle launches and the theoretical low angle trajectory they would use in a real attack against say the Western United States.

This calculus has changed a bit recently as they are using shallower angles to lob their missiles over Japan. Now they don't care if they antagonize others it seems.

Is the Universe finite or infinite? How does this affect the Big Bang theory? by MrOz1100 in askscience

[–]AsAChemicalEngineer[M] 0 points1 point  (0 children)

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If the universe started with a big bang, and I believe that it did, why is matter spread throughout the universe, and not simply in a single thin layer approximately 13 billion light years in every direction from where the big bang occurred? by [deleted] in askscience

[–]AsAChemicalEngineer 1 point2 points  (0 children)

Here's a FAQ about this question:


The short of it is that the big bang did not happen at a single point. It happened everywhere, the entire universe was in the distant past filled with a dense superhot soup which then expanded and cooled.

Expanded into what? you might ask. Most likely the universe is infinite in size and doesn't need to expand into anything. If this is hard to think about, an easy example is to consider a number line with every integer on it:

. . . -4 -3 -2 -1 0 1 2 3 4 . . .

This number line is infinite in extent, but the distance between each number is just one. Now if I multiply each number by two:

. . . -8 -6 -4 -2 0 2 4 6 8 . . .

This number line is also infinite, but the distance between each number is now two.

Is the Planck length constant or does it change as the universe expands? by jstaylor01 in askscience

[–]AsAChemicalEngineer 23 points24 points  (0 children)

The size of the Planck length is given by the Planck constant, speed of light and the gravitational constant G. There are hypotheses that these "constants" are not truly constant and thus the Planck units would change, but our current understanding of physics doesn't do this. The idea of constants changing is not new to physics, for example we know the coupling constants that determine the strength of fundamental forces changes with energy scale and there is some limited evidence that the fine structure constant which determines the strength of electromagnetism might change over billions of years—though I won't bet money on this last one being true, it's not necessarily ruled out and worth mentioning.

We know dramatically little about dark energy (what causes the accelerated expansion), but in the most simple models dark energy acts as another field in physics and doesn't break the rules like changing Planck's constant.

Also, is space time pixelated by this length[?]

Most likely not. Again, some people have explored ideas that do this, but there's as of yet no evidence for it. This idea also doesn't play nice with special relativity which means if has a lot of explaining to do before anybody takes it too seriously.

If I took a spoonful of matter from a neutron star and moved it away from the star, would it expand or stay compacted? by Dalem5 in askscience

[–]AsAChemicalEngineer 5 points6 points  (0 children)

It would explode and fly apart. It's super hot and the only reason its stuck together is the total gravity of the entire star.

What exactly is fire? by whitebarrys in askscience

[–]AsAChemicalEngineer 8 points9 points  (0 children)

Fire is a mix of plasma, thermally emitting soot, and light from specific atomic/molecular excitation. Depending on the fuel some of these flame components will be more important than others. A complete combustion butane torch burning blue will have nearly no soot (and thus no smoke) at all, but a campfire will have plenty of incomplete combustion and plenty of soot giving the characteristic orange glow from thermal emission.

Is the moon really about the same size of the sun in our sky? by superwester in askscience

[–]AsAChemicalEngineer 11 points12 points  (0 children)

Yup. The Moon is about 400 times closer to us than the Sun, but about 400 times smaller in diameter, so the difference in apparent size nearly cancels out.

Big coincidence

Yup. Good one too, or our eclipses wouldn't be quite so awesome.