Question Cyclical Universe

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Mar 19, 2020
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Cosmologists, however, that argue we are headed for a cold death vs. a hot one have demonstrable evidence from SN data alone that puts their claim, IMO, within mainstream science.
Been meaning to get back to this.

Are you referring to type II core-collapse supernovas and some data to indicate a cold death?

That could be interesting. Does it have anything to do with neutrinos?
 
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I really like the fluctuation idea. It seems that whenever the physicists have a problem, the fall back explanation is that it is caused by a "quantum fluctuation". Can't count how many times I have read this. It almost seems like crying "WOLF" too many times.

All the universe is presumed to result from a quantum fluctuation, so why can't everything else?

There is your theory of everything!
Thanks, i love simple solutions to what seem complex problems.
For sure nature doesn't have to make us happy, it does what it does and we need to see what it really is doing not what we would like it to do :)
 
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Jun 1, 2020
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Been meaning to get back to this.

Are you referring to type II core-collapse supernovas and some data to indicate a cold death?

That could be interesting. Does it have anything to do with neutrinos?
There's a great story about the two teams (Berkley & Harvard, 1998, IIRC) that were trying to independently refine the expansion rate (now the Hubble-Lemaitre Constant) with their new ability to locate and study S/N in distant galaxies. It was a race!

It is the Type 1a SN that produce a known luminosity, thus allowing their distance to be determined. With distance known, then with redshift revealing their recessional velocity, they would be able to tweak the H-L Constant (my abbrev.).

What both teams independently discovered was, shockingly, an accelerating rate of expansion for the universe.

You might enjoy how Harvard beat, barely, Berkley in the announcement. Harvard Obs. consisted of astronomers more so than physicists. Berkley had well known physicists (e.g. Perlmutter) and few astronomers, and fewer when one left to join Harvard. :)

For any SN study, one needs lots of time on very large telescopes, and that takes clout. Berkley seemed to have greater clout and, indeed, they had more SN observations by far over Harvard's number of SN.

The Harvard team, being astronomers, wisely chose to use multiple filters in their observations, thus their margin of error was less than Berkley's. So even with fewer data points, their's were more accurate. Thus, they could be more confident in drawing the stunning acceleration conclusion from their hard evidence.

But SN, Type 1a at least, also produce light profiles where they brighten quickly then fade away over time. So, if a SN, from the observations stated above, show great distance, then they will also be moving away from us the fastest. The result of this recessional motion can be seen in comparing the light profiles. A more distant SN will take more time to fade since they will be farther away from us over time. This also correlates to the expansion rate to help confirm the redshift is real.

The book that gave the account of both teams is quite interesting, and the author was more candid than expected about some frictional feelings between the two camps, which made the account even more real.
 
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There's a great story about the two teams (Berkley & Harvard, 1998, IIRC) that were trying to independently refine the expansion rate (now the Hubble-Lemaitre Constant) with their new ability to locate and study S/N in distant galaxies. It was a race!
Sorry if I am missing something from this but you said it played into a cold-death scenario.

This does not address that issue. It appears to be the first data to discover expansion, which was determined in 1998.

What are you, or what am I, missing?
 
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Sorry if I am missing something from this but you said it played into a cold-death scenario.

This does not address that issue. It appears to be the first data to discover expansion, which was determined in 1998.

What are you, or what am I, missing?
Oops. :)

With greater expansion comes greater cooling for the overall universe. Of course, for Earth, the Sun will expand and fry the Earth, but that will be in 4 or 5 billion years.

As the density decreases, so does the overall gravity field, so DE, in theory, may not only overpower gravity in the distant future but it may overpower all the forces so even molecules get ripped apart.
 
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Oops. :)

With greater expansion comes greater cooling for the overall universe. Of course, for Earth, the Sun will expand and fry the Earth, but that will be in 4 or 5 billion years.

As the density decreases, so does the overall gravity field, so DE, in theory, may not only overpower gravity in the distant future but it may overpower all the forces so even molecules get ripped apart.
Sad...
 
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Actually I was aware of these studies with "visible" objects, and this had been observed back in the late 1990s. But never heard of a "cold end" to the story. I have gotten a few cold-endings from some women, but not as a universal end-game, fortunately!

But how does a cold death reconcile with a warm death predicted by thermodynamics? :

From Wiki's "Entropy":

"Assuming that a finite universe is an isolated system, the second law of thermodynamics states that its total entropy is continually increasing. It has been speculated, since the 19th century, that the universe is fated to a heat death in which all the energy ends up as a homogeneous distribution of thermal energy so that no more work can be extracted from any source."

end quote.

Is it this "thermal energy" which defines the heat death? Cold is the lack of heat. So how does this work out? ->

Going further into Wiki, Here is something from "Heat death of the universe" :

"The heat death of the universe, also known as the Big Chill or Big Freeze, is a conjecture on the ultimate fate of the universe, which suggests the universe would evolve to a state of no thermodynamic free energy and would therefore be unable to sustain processes that increase entropy. Heat death does not imply any particular absolute temperature; it only requires that temperature differences or other processes may no longer be exploited to perform work. In the language of physics, this is when the universe reaches thermodynamic equilibrium (maximum entropy)."

end quote

The story goes on and on about a "heat death", rarely (if ever) bringing up "the Big Chill or Big Freeze" again (as used by others). Looks a tad on the confusing side. I find thermodynamics a more appealing definition : It is the "thermal energy" which defines the heat death. So, to get cold, one must presume it refers to the "death of heat", rather than the state of death (cold).

You cannot have both at the same time at infinity, or so it would seem......
 
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"Assuming that a finite universe is an isolated system, the second law of thermodynamics states that its total entropy is continually increasing. It has been speculated, since the 19th century, that the universe is fated to a heat death in which all the energy ends up as a homogeneous distribution of thermal energy so that no more work can be extracted from any source."

end quote.
Yes, the entropy of the universe is constantly increasing as the universe itself is the ultimate, and final, heat sink. It is receiving more and more heat. Thermodynamics (2nd law) addresses this process - a heat generating one. A "heat death" refers, IMO, to this process, such that when no more thermodynamic work can take place -- all systems like stars have fizzled out -- only heat is left. So...

Is it this "thermal energy" which defines the heat death?...
I think you're correct. Let's simplify and fix the universe for a given volume. We let all systems continue until all available energy is expended (trillions of years), and we know that power and work require a temperature differential, where, ultimately, space becomes the heat sink. At some point in this fixed universe only one temperature will exist and there will be no way to move energy from place to another that would produce any new work or power given no temperature differential.

...Cold is the lack of heat. So how does this work out? ->
So taking our fixed-sized universe above with a final and relatively low temperature from all that waste heat, and now we expand the universe, what happens? The temperature drops with every increment of expansion. So if we also include an accelerating rate of expansion, things will become very cold even quicker. I can see no other possibility.

"The heat death of the universe, also known as the Big Chill or Big Freeze, is a conjecture on the ultimate fate of the universe, which suggests the universe would evolve to a state of no thermodynamic free energy and would therefore be unable to sustain processes that increase entropy. Heat death does not imply any particular absolute temperature; it only requires that temperature differences or other processes may no longer be exploited to perform work. In the language of physics, this is when the universe reaches thermodynamic equilibrium (maximum entropy)."
Yes, though they seem to say it better than I did, except they failed to explain their own (apparent only) paradox. The dumping of waste heat into the universe is a heat process, but the net result, after more expansion, comes the Big Freeze.

You cannot have both at the same time at infinity, or so it would seem......
Right, the key is the expansion, which forces cooling, and, as my prof. stated in his thermobook, "Heat won't flow from a cooler to a hotter. You can try if you like but you far better notter!" :)
 
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Yes, the entropy of the universe is constantly increasing as the universe itself is the ultimate, and final, heat sink. It is receiving more and more heat. Thermodynamics (2nd law) addresses this process - a heat generating one. A "heat death" refers, IMO, to this process, such that when no more thermodynamic work can take place -- all systems like stars have fizzled out -- only heat is left. So...

I think you're correct. Let's simplify and fix the universe for a given volume. We let all systems continue until all available energy is expended (trillions of years), and we know that power and work require a temperature differential, where, ultimately, space becomes the heat sink. At some point in this fixed universe only one temperature will exist and there will be no way to move energy from place to another that would produce any new work or power given no temperature differential.



So taking our fixed-sized universe above with a final and relatively low temperature from all that waste heat, and now we expand the universe, what happens? The temperature drops with every increment of expansion. So if we also include an accelerating rate of expansion, things will become very cold even quicker. I can see no other possibility.

Yes, though they seem to say it better than I did, except they failed to explain their own (apparent only) paradox. The dumping of waste heat into the universe is a heat process, but the net result, after more expansion, comes the Big Freeze.

Right, the key is the expansion, which forces cooling, and, as my prof. stated in his thermobook, "Heat won't flow from a cooler to a hotter. You can try if you like but you far better notter!" :)
Couple things they overlooked with that idea.
When you expand at C relative to the start point things aren't ripped apart but are converted into energy and it has nowhere to go but inwards.
It can't violate faster than C outwards.

Time, if the expansion is indeed happening faster does the mechanism that is time also expand or simply the universe runs out of ability to produce enough time for events to continue?

Is the universe the mass and energy or is the universe quantum fluctuation with matter and energy as simple balanced E products?

A never ending increasing expansion of a universe also is a never ending expansion of E.
We don't detect a difference in E nor can we create or destroy it.

Minor detail like getting a atom sized universe energy black hole to begin this journey :)

Just some fuel for an interesting theory that hasn't looked into the details.
 
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Yes, though they seem to say it better than I did, except they failed to explain their own (apparent only) paradox. The dumping of waste heat into the universe is a heat process, but the net result, after more expansion, comes the Big Freeze.
We have all learned that energy cannot be created or destroyed. Some fool law of thermodynamics. So a Cold Death presumes, it would seem, that the universe can destroy energy, which is not something irrational since it is The Big Show, and it should be able to do "as it pleases".

But if the human concept is right, there will always be ER, just stretching longer and longer over time. This would seem to indicate the "heat death" takes an infinite amount of time to reach true 0 K. So "cold death" might get very close, but never really gets there.

From Wiki on "absolute zero":

"The laws of thermodynamics indicate that absolute zero cannot be reached using only thermodynamic means, because the temperature of the substance being cooled approaches the temperature of the cooling agent asymptotically, and a system at absolute zero still possesses quantum mechanical zero-point energy, the energy of its ground state at absolute zero. The kinetic energy of the ground state cannot be removed."

Perhaps the universe is not in total control after all. Quantum Mechanics always seem to have a way of gumming up the works. It would seem from this that true "cold death" is a hypothetical end-state that can never be reached.
 
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Don't you think that some of this might be a load of semantics?

It might depend on who you talk to.

Some will claim "it is all semantics" as the classic excuse to get out of a tough debate. Not sure that applies here. It does appear that no one is winning this debate. Rather, it seems unwinnable.

Indeed, this debate very much seems that it could stretch out to infinity......
 
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It might depend on who you talk to.

Some will claim "it is all semantics" as the classic excuse to get out of a tough debate. Not sure that applies here. It does appear that no one is winning this debate. Rather, it seems unwinnable.

Indeed, this debate very much seems that it could stretch out to infinity......
I don't usually give 'like's to posts containing the infinity word, but I have broken my general rule because of my massive respect for the poster :)
 
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We have all learned that energy cannot be created or destroyed. Some fool law of thermodynamics. So a Cold Death presumes, it would seem, that the universe can destroy energy, which is not something irrational since it is The Big Show, and it should be able to do "as it pleases".
No, the total energy (heat) is there but the energy density decreases with expansion. A decrease in energy density will decrease the temperature. At one point, the universe was perhaps 1 trillion degrees, so how did it cool? Expansion. Not dissimilar and perhaps very close to the ideal gas law.

But if the human concept is right, there will always be ER, just stretching longer and longer over time. This would seem to indicate the "heat death" takes an infinite amount of time to reach true 0 K. So "cold death" might get very close, but never really gets there.
Yes, but things will have died long before the almost 0 K point, right? But things can remain "alive", IMO, during all the events that dump heat into the great heat sink.

But if the universe were of a fixed size, then perhaps all that waste heat would overcome all that is alive. Yet an accelerating expansion suggests that the cooling effects will overcome the heat density. [Added: The current temperature of the universe now is only 2.73K, thus how can any sort of heat death come about?]

"The laws of thermodynamics indicate that absolute zero cannot be reached using only thermodynamic means, because the temperature of the substance being cooled approaches the temperature of the cooling agent asymptotically, and a system at absolute zero still possesses quantum mechanical zero-point energy, the energy of its ground state at absolute zero. The kinetic energy of the ground state cannot be removed."
Ok, but since all that waste heat isn't "destroyed", then O K can never be reached regardless of expansion. Just as you can't have absolute zero density given even 1 gram of matter for any volume. But, in general, at some point it can easily be treated as zero, just as we don't require a huge number of decimal places for our use of temperature values.

Perhaps the universe is not in total control after all. Quantum Mechanics always seem to have a way of gumming up the works. It would seem from this that true "cold death" is a hypothetical end-state that can never be reached.
I'll go with your judgement on that one as it seems likely.
 
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To add to this concept, it must be appreciated that infinity is actually an absolute definition foisted on us by those fool mathematicians who allow for the actual manipulation of numerology with data to reveal such absurdities.

At any rate, if we assume that the universe must reach absolute zero K for true cold death (which seems in my brief readings to be the benchmark for this story line), just to be brief, than it will never reach it because of mathematical calculations of the temperature throughout the countless eons of expansion.

One might suggest you can measure the temperature down to -50 orders of magnitude above absolute zero. After reaching this temperature, extrapolation models (and that pesky mathematics) provide reasonable assurances that the declining value will always be above absolute zero, and never hit zero regardless of how low the numbers seem to go. Keep in mind, these are numbers that never end, just like the expansion!

Thus the universe might more appropriately be called having an infinitely slow heat death, and never quite dies away.
 
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So, we've just ruled out the Heat Death theory. Brilliant!

Yeah, as far as I know ( I don't know much), reaching 0 kelvin is impossible. And, even if you try to reach 0 K, it will take forever. (Semantics!)

So, the Universe will never die. Yipee!
 
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