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Author | Topic: Thermodynamics and The Universe | |||||||||||||||||||||||||||||||
cavediver Member (Idle past 3643 days) Posts: 4129 From: UK Joined: |
In the recently closed thread, our new member EODoc made some claims regarding the nature of the universe, inspired by consideration of the laws of Thermodynamics. These are oft-repeated claims by the creationist crowd and I would like to propose a thread where we can discuss this.
I open with my reply to EODoc but would encourage others to join in with comments, questions and refutations Big Bang & Comsology of course!
In short, the fact that we exist demonstrates that possibility 1 cannot be true because if the universe is infinitely old then such a state (the heat death) would have already been reached. Heat death is a state that exists in an open or flat Friedmann ( or closed Lemaitre ) Robertson Walker universe. None of these are universes that have always existed. There are many possibilities for eternally existing universes that do not have thermodynamic problems. Next?
I hope you can see quite clearly that if the universe created itself then we have a little problem called the first law of thermodynamics. Let me know if you need me to expound on what the 1st law is in real terms. Please do, as I would love to hear your ideas on thermodynamics in a closed universe. First off perhaps you would like to define "energy" as that seems rather important for your 1LoT. And what would happen to your 1LoT as your definition of energy breaks down and becomes fairly meaningless (as all mine do when we get back toward t=0 in a F(L)RW universe)
I hope you can see quite clearly that if the universe created itself then we have a little problem called the first law of thermodynamics No, on the contrary, the 1LoT has the problems when we enter regions of the universe where naive ideas of energy and heat and such-like make little to no sense.
I don't think you can argue against this except by saying that the laws of thermodynamics don't apply to the universe as a whole but it would be hard to make such an argument based on known science Thermodynamics applies to systems of multitudes of classical particles. To consider the Universe as a whole is to have one very unclassical particle. How exactly does Thermod even begin to apply?
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AdminNosy Administrator Posts: 4754 From: Vancouver, BC, Canada Joined: |
Thread moved here from the Proposed New Topics forum.
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happy_atheist Member (Idle past 4913 days) Posts: 326 Joined: |
cavediver writes: Thermodynamics applies to systems of multitudes of classical particles. This was one of the most amazing things I saw when I was studying physics. I hated thermodynamics, but when I took a statistical mechanics course and saw the well known 'laws' drop out from simple quantumn mechanics (ha!) and some approximations that can only be made with extremely large numbers of particles it was quite eye opening. I only wish I'd been better at physics overall so I could have made a go of it. Seeing this thread again has made me want to go find my physics texts and start learning all over again! But it does bring to light how hard it is for a non-physicist to grasp how their every-day point-of-view governed by common sense rules is totally non-applicable to the universe as a whole. I certainly look forward to EODoc's response (or anyone else who decides to take the challenge).
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Chiroptera Inactive Member |
Hey, cavediver. Wave me off if this is getting off of the topic you wanted to discuss.
I do find it amusing that people try to apply "physical laws", which are used to describe phenomena within the universe, to the "creation of the universe" (whatever that even means!) itself. Take the law of conservation of energy, for example. Even beside the very good points you made, the law of conservation of energy simply states that at each point in time, the energy of a closed system will remain the same. Well, the "creation of the universe" certainly does not violate this. "Before" the universe existed, there was no time -- hell, "before the universe existed" is itself a nonsensical phrase. "Before" the creation of the universe, there were no "points of time". So even in a classical universe existing for a finite amount of time, there is no violation of the law of conservation of energy: there was no point in time when the energy content of the universe was different. God, what a weird topic. This is going to wear out the quote key on my keyboard. This world can take my money and time/ But it sure can't take my soul. -- Joe Ely
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cavediver Member (Idle past 3643 days) Posts: 4129 From: UK Joined: |
I do find it amusing that people try to apply "physical laws", which are used to describe phenomena within the universe, to the "creation of the universe" Yep, though scientists have been guilty of this in trying to explain creation ex nihilo in terms of pair-creation and the like!
So even in a classical universe existing for a finite amount of time, there is no violation of the law of conservation of energy: there was no point in time when the energy content of the universe was different. Nicely put... will use that myself It's easier than trying to explain the breakdown in definition of energy at the t=0 point.
God, what a weird topic. This is going to wear out the quote key on my keyboard. Yeah, noticed that myself a month or so back, where every fourth word I wrote was in "quotes"... I guess it's that or bring out the heavy maths. You may now appreciate what I meant a while back when I said that very few scientists actually have a real grasp of the Big Bang. All the bits for t > 10e-33s are easy, it's that bit from t=0 that gets you
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cavediver Member (Idle past 3643 days) Posts: 4129 From: UK Joined: |
This was one of the most amazing things I saw when I was studying physics. I hated thermodynamics, but when I took a statistical mechanics course and saw the well known 'laws' drop out from simple quantumn mechanics (ha!) and some approximations that can only be made with extremely large numbers of particles it was quite eye opening. Funny, I was exactly the same. I still hate traditional TD but stat mech is fascinating.
Seeing this thread again has made me want to go find my physics texts and start learning all over again! Then my job is done
But it does bring to light how hard it is for a non-physicist to grasp how their every-day point-of-view governed by common sense rules is totally non-applicable to the universe as a whole Quite. And it's not just the non-physicist. EODoc is a perfect example of a physicist (physical chemist) who is a complete fish-out-of-water when it comes to considering fundemental cosmology - no better and in fact considerably worse than many of the well-informed laymen who frequent EvC. To be fair, my knowledge of chemistry is pretty awful...
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Percy Member Posts: 22392 From: New Hampshire Joined: Member Rating: 5.2 |
cavediver writes: Quite. And it's not just the non-physicist. EODoc is a perfect example of a physicist (physical chemist) who is a complete fish-out-of-water when it comes to considering fundemental cosmology - no better and in fact considerably worse than many of the well-informed laymen who frequent EvC. To be fair, my knowledge of chemistry is pretty awful... I fear we may have lost EODoc, I haven't seen him since AdminPD closed that other thread. My knowledge of chemistry is pretty bad, too, but we are both cognizant of how little we know of chemistry. How does someone, anyone, reach the PhD level without passing association with so much knowledge as to force the realization of how little one knows. One thing you can say for EODoc, though - he sure wasn't afraid to make a mistake! --Percy
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SplifChief Junior Member (Idle past 6248 days) Posts: 5 From: FL Joined: |
Hi there. I know I am just jumping in, but I just wanted to contact you. I posted a question that admin said didn't justify a thread, but suggested that maybe you could answer.
How can the observable universe be larger than the age of the universe if nothing travels faster than the speed of light? If for example 2 elements were relatively close at the BB, and now one is in our galaxy and the other in the far reaches of the observable universe, how could it have traveled more than 13+ light years away given the time it has been traveling? Please excuse any misuse of terms, just trying to get my question across in an attempt to get past this mental block. Thanks
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kuresu Member (Idle past 2513 days) Posts: 2544 From: boulder, colorado Joined: |
i don't know if this answer is right, but . . .
our universe is 13 billion years old. let's picture the universe as a beach ball. the center of this ball is where the big bang occurred. light travels in all directions from the center. the universe (beach ball) is thus 26 light years in diameter. the age, then, is the radius. again, not sure if this is the right answer, but . . . oh, and welcome to the boards. Question. Always Question. " . . .and some nights I just pray to the god of sex and drugs and rock'n'roll"--meatloaf Want to help give back to the world community? Did you know that your computer can help? Join the newest TeamEvC Climate Modelling to help improve climate predictions for a better tomorrow.
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NosyNed Member Posts: 8996 From: Canada Joined: |
If you had browsed, tediously, the cosmology threads you would find reference to the fact that the expansion of the universe is NOT anything moving through space (which is limited to light speed). It is the expansion of space itself. This is not limited to light speed.
The expansion between two points in space is proportional to the distance between them. At some point this means that two galaxies may be receding from each other at greater than light speed even if they are not moving. If that is confusing try this analogy. Put ants on a big sheet of rubber. Now stretch the rubber bigger and bigger. The ants get further apart without 'moving' (on the sheet) at all. Ants that started further apart have more stretching rubber between them so they move apart faster than ants that started closer together.
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SplifChief Junior Member (Idle past 6248 days) Posts: 5 From: FL Joined: |
OK, so I think I've got it now. The expansion of space itself is not subject to any speed limitations.
Should this give the appearance of a stretching affect as we observe light from these galaxies moving with space at speeds greater than the speed of light?
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NosyNed Member Posts: 8996 From: Canada Joined: |
Should this give the appearance of a stretching affect as we observe light from these galaxies moving with space at speeds greater than the speed of light? Yes, this is the "red shift" you read about a lot. As the recession velocity goes up the light from a given galaxy is shifted (stretched) to longer and longer wave lengths. As the recession velocity approaches c (light speed) the wave length is stretched to infinity and the galaxy is no longer visible. (warning: I'm an amateur so wait for cavediver's corrections before swallowing completely)
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Buzsaw Inactive Member |
Chiroptera writes: So even in a classical universe existing for a finite amount of time, there is no violation of the law of conservation of energy: there was no point in time when the energy content of the universe was different. 1. The above statement as well as if the universe is a closed and finite system makes my point in another thread that there indeed was no before the universe and no outside of the universe if it is a closed, bordered and finite system. Thus our resident Biblical theists do indeed have the problem that I raised in my thread that the Biblical god in whom they believe could not possibly exist on the basis of such a universe. 2. I don't see how you can exempt laws of physics from the science of a system origin hypothesis which itself defies the the laws observed within the system. Isn't that what you are forbidding ID creatonists to do? Essentially you are assuming that the entire energy of the universe popped into existence suddenly from nothing. The only other alternative is that the Universe is infinite without beginning or end as we claim for the intelligent designer, the source of all existing energy. BUZSAW B 4 U 2 C Y BUZ SAW ---- Jesus said, "When these things begin to come to pass, then look up, and lift up your heads, for your redemption draws near." Luke 21:28
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jar Member (Idle past 394 days) Posts: 34026 From: Texas!! Joined: |
Thus our resident Biblical theists do indeed have the problem that I raised in my thread that the Biblical god in whom they believe could not possibly exist on the basis of such a universe. ROTFLMAO No problems for the GOD we believe in Buz, just for the little crappy goddlet you created and worship. But what does any of that have to do with the Topic? Aslan is not a Tame Lion
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Doddy Member (Idle past 5909 days) Posts: 563 From: Brisbane, Australia Joined: |
NosyNed writes: As the recession velocity approaches c (light speed) the wave length is stretched to infinity and the galaxy is no longer visible. I remember reading that this isn't true, but I can't remember the theoretical reasoning. But I do know that we can see galaxies outside of the Hubble sphere (which were receding superluminally when they emitted the photons that our telescopes can see). I'll have to wait for the explanation too. Something about the Hubble sphere growing, I think...? "Der Mensch kann was er will; er kann aber nicht wollen was er will." (Man can do what he wills but he cannot will what he wills.) - Arthur Schopenhauer
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