Science fleeting thoughts

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Re: Science fleeting thoughts

Postby p1t1o » Thu Jun 20, 2019 2:01 pm UTC

Fair.

Especially in the case of bankers where it is literally true XD

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Re: Science fleeting thoughts

Postby ijuin » Thu Jun 20, 2019 2:04 pm UTC

The figures I used were meant to represent how much money the employer gets from the work, NOT the employee. My entire point was that the amount paid to the employee does NOT reflect how valuable the work is to the boss, but rather only reflects how difficult it is for the boss to get another qualified candidate—therefore, a worker who is easily replaced will get lower pay even if that worker’s job contributes more to the company’s bottom line than a less-replaceable worker who does a different job.

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Re: Science fleeting thoughts

Postby Eebster the Great » Thu Jun 20, 2019 4:23 pm UTC

Astronauts do eventually retire. Training new astronauts is more expensive than paying old ones. I don't think the pay has anything to do with the cost of replacement here, I think it has to do with inflexible government pay grades. I think if you paid astronauts more, causing them to stay on longer than average, you might even save money. Alternatively, you might just get better candidates. I think the idea that money is not motivating for potential astronauts is false. It's a little like saying there's no point paying replacement football players anything, because they're in it for the love of the game.

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Re: Science fleeting thoughts

Postby p1t1o » Fri Jun 21, 2019 8:06 am UTC

Well theres a lot of grey area between paying footballers 10's of K per week and zero lol!

Astronauts get paid a surprisingly small amount, but they get a pretty good salary. Wonder if footballers would play for that amount.

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Re: Science fleeting thoughts

Postby solune » Fri Jun 21, 2019 9:32 am UTC

Eebster the Great wrote:Don't you think at least a few of them would prefer to carry up only 12 oz of personal items in exchange for $6,000 extra pay?


Sorry for being late to the party, but I think there is something missing here. NASA/ESA/Roscosmos pay a lot of expensive psychiatrists, and (I assume) their opinion is that allowing 700g of personal items is beneficial to the state of mind of the astronauts. The astronauts are more effective as their job as a result of that, and they generate more than 12,000 $ worth of supplemental SCIENCE!.
Which is why the management didn't ask for the astronauts opinion.

An example of astronauts being ineffective at their jobs: the Skylab mutiny, costing somewhere around 20 M$, and the Apollo 7 incident (I don't have an estimate of the costs for this one).

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Re: Science fleeting thoughts

Postby p1t1o » Fri Jun 21, 2019 11:04 am UTC

Was 600g of <PERSONALEFFECTS> not enough for sanity?

What <PERSONALEFFECTS> have the greatest impact on sanity I wonder? 12oz of photos is a lot, but 12oz of beef jerky, not so much.

But photos of family members could reduce sanity! Either via enhancing homesickness or reminding them what is waiting for them back on Earth ;)

But mmmmmmm, beef jerky.

I wonder what the optimum sanity-preserving collection of things is.

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Re: Science fleeting thoughts

Postby ijuin » Fri Jun 21, 2019 2:31 pm UTC

24 oz is a trivial amount of mass compared to life supply requirements anyway—any astronaut consumers quadruple that in water and food per day. I would think that conversely, astronauts would be willing to forgo the equivalent of a single bottle of water in exchange for an extra pound of personal allowance.

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Re: Science fleeting thoughts

Postby Eebster the Great » Fri Jun 21, 2019 5:09 pm UTC

A lot of water gets recycled, so that's not quite true. Anyway, NASA isn't going to budge on something as important as water. The Skylab incident in my mind supports what I'm saying--astronauts were fed up with work and chose to stop doing it, costing NASA millions. If there were a financial incentive not to do that, it might not have happened. And it sort of flies in the face of the claim that there is no need to pay astronauts more when they are in space, because they're already just so excited to be there.

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Re: Science fleeting thoughts

Postby Quizatzhaderac » Fri Jun 21, 2019 6:18 pm UTC

I've very skeptical of the idea that astronauts could simply make a rational choice to work harder. Going by practices of America's elite military organizations, they would be worked at close to a person's philological limitations, and the physiological limitations are only mapped out when incidents occur.
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Re: Science fleeting thoughts

Postby Sableagle » Sat Jun 22, 2019 1:49 am UTC

The amount of energy in a photon depends on the energy levels between which an electron descended when that photon was emitted.
The wavelength of a photon depends on its energy, with longer wavelengths having lower energies.
Every element (isotope?) has its own distinct set of energy levels, which gives them distinctive sets of wavelengths of light they emit when excited, aka distinctive flame colours.
The differences between energy levels decrease as the energy levels get higher, causing the lines of the emission spectra to beome closer together at the short wavelength side of each series.
If an electron gets enough energy, it'll pass its host element's maximum energy level and become dissociated from it, forming (partial) plasma.

Right?

Shouldn't all that mean there's a minimum amount of energy that any element can lose, and therefore a minimum temperature and, barring the expansion of space itself, a maximum wavelength?
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Re: Science fleeting thoughts

Postby Eebster the Great » Sat Jun 22, 2019 3:35 am UTC

There might be a minimum temperature for other reasons, but photon emission is not the only or even main way atoms transfer energy to each other.

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Re: Science fleeting thoughts

Postby ijuin » Sat Jun 22, 2019 3:43 am UTC

This issue of energy still being greater than zero yet still unable to decrease is what is called the zero point energy. When matter cools to absolute zero, there is still energy left that can not be extracted because there are no more permissible transitions to lower-energy states.

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Re: Science fleeting thoughts

Postby Eebster the Great » Sat Jun 22, 2019 4:23 am UTC

The notion of a minimum temperature is not off the table though. 0 K is a lower bound (excluding negative temperatures), but it might not be the greatest lower bound, and it's definitely not a minimum, since it is unattainable. There might be a physically attainable positive temperature which is lower than all other attainable positive temperatures, but I can't remember what it's called.

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Re: Science fleeting thoughts

Postby gmalivuk » Sat Jun 22, 2019 12:17 pm UTC

Sableagle wrote:Shouldn't all that mean there's a minimum amount of energy that any element can lose, and therefore a minimum temperature and, barring the expansion of space itself, a maximum wavelength?

Not only is photon emission not the only way atoms transfer energy, it's also far from the only way photons or EM waves are produced. I don't know how you could broadcast AM or FM signals if you could only produce radio waves at the precise wavelengths of energy transitions in atoms and molecules.
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Re: Science fleeting thoughts

Postby ijuin » Sat Jun 22, 2019 4:22 pm UTC

Eebster the Great wrote:The notion of a minimum temperature is not off the table though. 0 K is a lower bound (excluding negative temperatures), but it might not be the greatest lower bound, and it's definitely not a minimum, since it is unattainable. There might be a physically attainable positive temperature which is lower than all other attainable positive temperatures, but I can't remember what it's called.

If there is such a lower bound, then it is below 100 picokelvins, since such a temperature has already been achieved in laboratories.

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Re: Science fleeting thoughts

Postby Ciber » Tue Jun 25, 2019 2:31 pm UTC

Just had a thought. After the black hole era, once the universe has cooled sufficiently, is there any reason to expect new interesting physics at such extremely low energies? Some symmetries broke in the past, could there be another symmetry breaking event awaiting us in the deep future?

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Re: Science fleeting thoughts

Postby ijuin » Tue Jun 25, 2019 5:29 pm UTC

Hmm, well, for one thing, at such low temperatures, spontaneous quantum tunneling over macroscopic distances would become common. Even with current ultracold experiments, tunneling occurs over distances of millimeters. Sufficiently cold environments would allow tunneling over kilometers or more.

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Re: Science fleeting thoughts

Postby solune » Wed Jun 26, 2019 1:35 pm UTC

But the universe will be cold because it's extremely dilated though. Will there be any particle of relevance within several kilometers ?

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Re: Science fleeting thoughts

Postby p1t1o » Wed Jun 26, 2019 3:14 pm UTC

solune wrote:But the universe will be cold because it's extremely dilated though. Will there be any particle of relevance within several kilometers ?


There is a non-zero probability that there will be, and spontaneous entropy reversals would occur, given near infinite timescales.

IIRC, quantum tunneling can happen over *any* distance, just the probabilities get extremely low.

From some light googling, the physics of the deep, deep future depends greatly on the exact nature of dark matter/energy, which we still have little knowledge of, so much is still unknown about these timescales.

Is proton decay still up-in-the-air?

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Re: Science fleeting thoughts

Postby solune » Wed Jun 26, 2019 10:05 pm UTC

So you're saying that Boltzmann brains will occur in this universe if we just wait for it.

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Re: Science fleeting thoughts

Postby cyanyoshi » Wed Jun 26, 2019 10:33 pm UTC

solune wrote:So you're saying that Boltzmann brains will occur in this universe if we just wait for it.

It should be mentioned that just because something is possible doesn't mean it's a safe bet that it will ever happen, even with infinite time.

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Re: Science fleeting thoughts

Postby Xanthir » Wed Jun 26, 2019 11:10 pm UTC

I mean, with infinite time all things that are possible will happen.
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Re: Science fleeting thoughts

Postby Pfhorrest » Thu Jun 27, 2019 12:16 am UTC

Not necessarily. It is possible in principle that the same finite pattern might just repeat infinitely, and some things might not occur in that pattern, and so never occur even in infinite repetitions of it.
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Re: Science fleeting thoughts

Postby Eebster the Great » Thu Jun 27, 2019 1:47 am UTC

If we put the universe in a box of constant volume, it's inevitable that a given state would eventually recur, thus putting the universe in an infinite loop. But for an infinitely expanding universe, that needn't happen. But in that case, there may be infinitely many "possible" states, so not every one (or even most) need be guaranteed. Indeed, if the number of possible states increases exponentially with time, only a measure zero subset could ever occur even in a universe infinite in duration.

After infinitely many trials, any event with constant nonzero probability (or probability with a nonzero lower bound) will occur with 100% probability. But an event with diminishing nonzero probability for each trial can have any overall probability of occuring at least once, except 0.

If I had to guess, the probability of a Boltzmann Brain ever forming is probably very, very small.

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Re: Science fleeting thoughts

Postby p1t1o » Thu Jun 27, 2019 8:09 am UTC

So if the universe were static and not expanding, the probability over infinite time of a Boltzmann brain would be 1?

What does that say about a contracting universe?

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Re: Science fleeting thoughts

Postby solune » Thu Jun 27, 2019 8:26 am UTC

My understanding of the big freeze theory is that after a while the expansion rate stabilises (or at least only increases polynomially). So (without doing any math) I'd think the probability of the Boltzmann brain converges to 1.

Additionnaly I don't think there are an exponentially increasing number of states. Since we're talking only about particles poping out of the void, for a given chunk of space, the most probable states will be of a limited number of particles with low energy levels. Which is exactly where quantum theory tells us that there is a limited number of states.

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Re: Science fleeting thoughts

Postby Eebster the Great » Thu Jun 27, 2019 9:34 am UTC

p1t1o wrote:So if the universe were static and not expanding, the probability over infinite time of a Boltzmann brain would be 1?

What does that say about a contracting universe?

Not necessarily, because in a static universe, you would get eternal recurrence. There is no reason to expect that cycle to hit every possible state during its finite period. A contracting universe is finite in duration (unless it's a cyclical scenario, in which case see my last sentence), so you will only get finitely many states.

solune wrote:My understanding of the big freeze theory is that after a while the expansion rate stabilises (or at least only increases polynomially). So (without doing any math) I'd think the probability of the Boltzmann brain converges to 1.

No, the scale factor is definitely exponential in time. Currently expansion is superexponential, as the rate of expansion is increasing as the universe becomes increasingly more dominated by dark energy and less by matter. If the Hubble parameter is constant, that means the universe is expanding exponentially.

Additionnaly I don't think there are an exponentially increasing number of states. Since we're talking only about particles poping out of the void, for a given chunk of space, the most probable states will be of a limited number of particles with low energy levels. Which is exactly where quantum theory tells us that there is a limited number of states.

That limited collection of states is not what was asked about, though. Things like Boltzmann brains by definition take you very far away from anything like a probable state. These are monstrosities of improbability on the order of the reciprocal of googolplex just for the tunneling of a single particle over such a distance.

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Re: Science fleeting thoughts

Postby Xanthir » Thu Jun 27, 2019 9:21 pm UTC

Pfhorrest wrote:
Not necessarily. It is possible in principle that the same finite pattern might just repeat infinitely, and some things might not occur in that pattern, and so never occur even in infinite repetitions of it.

By definition, then, the thing that doesn't happen isn't possible. It might be *plausible*, given an incomplete understanding of the dynamics of the system, such that a limited human mind can imagine the thing happening, but if the system is indeed cyclic and the thing isn't in that cycle, then it's not possible.

I mean, this is semantics, but still.
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Re: Science fleeting thoughts

Postby Pfhorrest » Thu Jun 27, 2019 9:32 pm UTC

It is semantics. It's the difference between "possible" as in "is a point in the configuration space" which I meant, and "possible" as in "is a point in the configuration space that the system actually moves through" which you meant.

Consider a string of digits. It is possible to have any digit appear anywhere in that string of digits: there is some possible number where that digit appears in that place. A string of digits corresponding to the decimal representation of any irrational number will eventually have every digit appear in some place or another. (I think? Or maybe just some subset of them, transcendentals maybe? Pi definitely.) But strings corresponding to decimal representations of rational numbers won't necessarily ever feature some digit. So just because it's possible for a 5 to show up somewhere in a string of digits, and given the right kind of process generating those digits (like pi) then given infinity you will eventually find any digit you want, or any string of digits you want, but if the process generating the digits is, say, dividing one by six, then you're never going to run into a 5 anywhere in there, as it'll get stuck repeating 6's forever in short order.
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Re: Science fleeting thoughts

Postby Eebster the Great » Thu Jun 27, 2019 10:33 pm UTC

Yeah, if "possible" just means "actually happens," then by definition all possible things happen regardless of the size or age of the universe. But that's not very interesting to talk about.

By the way, the property you are thinking of is not irrationality but normalcy. A normal number in a base b contains every string of digits less than b somewhere in its base b expansion. No number has ever been proved to be normal in any base except numbers deliberately constructed to be so. But many irrational numbers like pi are believed to be normal in every base. Some irrational numbers can be easily proved not to be normal in any base, and rational numbers can never be normal, since they repeat.

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Re: Science fleeting thoughts

Postby Xanthir » Thu Jun 27, 2019 10:47 pm UTC

Yeah, "possible" is usually (at least, by me?) interpreted to mean "has a non-0% chance of happening" or in the case of infinitesimal chances, "0% but not impossible". Thus something not in the path that a space would move thru is not possible. "in the phase space" is what I would call "plausible", meaning that, given the evidence at hand and my computational resources, I can't rule out it being possible.

Yeah, if "possible" just means "actually happens," then by definition all possible things happen regardless of the size or age of the universe. But that's not very interesting to talk about.

I mean, when you're discussing infinite time, yeah. "Possible" things don't have to happen if you're asking about a finite time scale, so that's plenty interesting to talk about. ^_^
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Re: Science fleeting thoughts

Postby Eebster the Great » Thu Jun 27, 2019 10:50 pm UTC

Xanthir wrote:
Yeah, if "possible" just means "actually happens," then by definition all possible things happen regardless of the size or age of the universe. But that's not very interesting to talk about.

I mean, when you're discussing infinite time, yeah. "Possible" things don't have to happen if you're asking about a finite time scale, so that's plenty interesting to talk about. ^_^

I don't see how. The finite age of such a universe imposes a constraint that makes it impossible to reach these events. Thus they can't happen. Assuming the universe is deterministic, then every possible thing by your definition happens, since for everything that doesn't happen, there is some physical reason why it couldn't.

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Re: Science fleeting thoughts

Postby Xanthir » Thu Jun 27, 2019 11:04 pm UTC

Eh okay, you got me, in a deterministic universe any finite length of time you observe also has events only occurring either 100% of the time or 0% of the time.

So let's go back to a realistic example of a universe with quantum randomness. ^_^ In such a case, there is no possibility of cycling, as there's no reason for a path to repeat between iterations, even if there is a singularity that it expands from and returns to. So we're back to anything that's "possible" (in the phase space) as being "possible" (will occur in infinite time).
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Re: Science fleeting thoughts

Postby cyanyoshi » Thu Jun 27, 2019 11:22 pm UTC

Xanthir wrote:Yeah, "possible" is usually (at least, by me?) interpreted to mean "has a non-0% chance of happening" or in the case of infinitesimal chances, "0% but not impossible". Thus something not in the path that a space would move thru is not possible. "in the phase space" is what I would call "plausible", meaning that, given the evidence at hand and my computational resources, I can't rule out it being possible.

It's important to realize that no prediction in science is 100% certain. When I say that an outcome is possible, I mean that it cannot be ruled out based on our current level of knowledge, not that it is definitely going to happen.

Edit:
Xanthir wrote:Eh okay, you got me, in a deterministic universe any finite length of time you observe also has events only occurring either 100% of the time or 0% of the time.

So let's go back to a realistic example of a universe with quantum randomness. ^_^ In such a case, there is no possibility of cycling, as there's no reason for a path to repeat between iterations, even if there is a singularity that it expands from and returns to. So we're back to anything that's "possible" (in the phase space) as being "possible" (will occur in infinite time).

Consider the following. You start with no money. Every time you flip a coin, you get $2 if heads, and $1 if tails. Would you agree that having exactly $10 at some point is possible, but not sure to happen?

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Re: Science fleeting thoughts

Postby chridd » Tue Jul 09, 2019 11:06 am UTC

cyanyoshi wrote:Consider the following. You start with no money. Every time you flip a coin, you get $2 if heads, and $1 if tails. Would you agree that having exactly $10 at some point is possible, but not sure to happen?
It's not possible, since if you don't have any money, you don't have any coins to flip, since coins are money. :twisted:
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Re: Science fleeting thoughts

Postby ijuin » Tue Jul 09, 2019 2:21 pm UTC

Assume that it is a non-legal-tender coin.

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Re: Science fleeting thoughts

Postby p1t1o » Tue Jul 09, 2019 2:37 pm UTC

It only says you start with no money. I started with no money and now I have like, 8 coins. And I also hope one day to have $10.

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Re: Science fleeting thoughts

Postby Quizatzhaderac » Tue Jul 09, 2019 5:19 pm UTC

So I've been thinking about cosmic expansion and quantum states.

If we have a hydrogen atom floating in a void in an expanding universe. The "space" between the electron and proton should be increasing, which I would interpret as saying the probability cloud stays the same shape, but increases average distance. Eventually, the electron will be far enough away that it will be able to spontaneously emit a photon.

This would look like atoms emitting energy very slightly beyond what the Stefan–Boltzmann law calls for (and in fact beyond what conservation of energy would allow in static space). Also, I would expect to see random minor nuclear reactions noise, the likes of which we see when look for neutrinos or dark matter.

Something similar would happen between quarks in baryons, but there's a very important difference. The energy difference between an electron in a S1 orbital and infinity is finite and much smaller than the resting energy of an electron. The energy difference in moving quarks from adjacent to infinity is infinite; in fact, moving a set of quarks apart produces additional quarks.

So in a big rip scenario: a single nucleon is converted into an arbitrarily large cloud of neutronium, which is massive and slows expansion.

Sableagle wrote:If an electron gets enough energy, it'll pass its host element's maximum energy level and become dissociated from it, forming (partial) plasma.
There's an infinite number of energy levels that the electron could theoretically go through as it becomes less tightly bound to it's nucleus.

A dissociated electron can be though of as being in a very complex hybrid orbital between multiple nuclei, where it's loosely bound to each. Since the orbital is so complex, so subject to arbitrary change, and the energy quanta are so small, it just becomes useless to talks about specific orbitals the electron is in. Also (I think) it's be pretty common for electrons to not be more that 50% likely to be in any one orbital.

There is no distinct line between an electron being associate and being disassociated. Well, I guess if an electron has too much kinetic energy to be bound to any nuclei, that's unambiguously disassociated, but there's still that grey area of we-can't-possibly-count-the-associations between unambiguously associated and unambiguously disassociated.

Eebster the Great wrote:If we put the universe in a box of constant volume, it's inevitable that a given state would eventually recur, thus putting the universe in an infinite loop. But for an infinitely expanding universe, that needn't happen.
An expanding universe would have a horizon, and thus a limited "visible universe" within. The greater the expansion, the smaller the visible universe and the fewer possible states. So in a sense, an expanding universe is necessarily finite.
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Re: Science fleeting thoughts

Postby Eebster the Great » Tue Jul 09, 2019 6:22 pm UTC

Quizatzhaderac wrote:So I've been thinking about cosmic expansion and quantum states.

If we have a hydrogen atom floating in a void in an expanding universe. The "space" between the electron and proton should be increasing, which I would interpret as saying the probability cloud stays the same shape, but increases average distance. Eventually, the electron will be far enough away that it will be able to spontaneously emit a photon.

No, the energy levels are quantized. The electron can't ever be excited by metric expansion unless it's happening dozens of orders of magnitude faster than it is now.

Sableagle wrote:If an electron gets enough energy, it'll pass its host element's maximum energy level and become dissociated from it, forming (partial) plasma.
There's an infinite number of energy levels that the electron could theoretically go through as it becomes less tightly bound to it's nucleus.

There are infinitely many energy levels, but they are bounded as you pointed out, so with more energy than that, the electron escapes to infinity.

Eebster the Great wrote:If we put the universe in a box of constant volume, it's inevitable that a given state would eventually recur, thus putting the universe in an infinite loop. But for an infinitely expanding universe, that needn't happen.
An expanding universe would have a horizon, and thus a limited "visible universe" within. The greater the expansion, the smaller the visible universe and the fewer possible states. So in a sense, an expanding universe is necessarily finite.

It's not the case that the observable universe necessarily shrinks in an expanding universe. It can eternally expand itself.

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Re: Science fleeting thoughts

Postby Quizatzhaderac » Tue Jul 09, 2019 7:22 pm UTC

Eebster the Great wrote:No, the energy levels are quantized. The electron can't ever be excited by metric expansion unless it's happening dozens of orders of magnitude faster than it is now.
What are you suggesting is the time limit for this effect to occur?

Gravity is also quantized1, and any rounding down effect is negligible (or space is expanding faster than we think, but the rounding artifacts produce the rate we believe). Gravity is "dozens of orders" weaker that EM, but still the Hubble constant is smaller enough that we'd still see noticeable time gaps between gravitational excitations.
It's not the case that the observable universe necessarily shrinks in an expanding universe. It can eternally expand itself.
As it expands, parts of it become unobservable to other parts; the faster the expansion, the smaller any observer's observable universe. An observable universe of constant expansions has a radius inversely proportional to it's Hubble constant.

The contents of the box are eternally expanding, but they contents become casually disconnected from each other, so in an important sense, they stop being in the same universe.
The thing about recursion problems is that they tend to contain other recursion problems.


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