Is the Universe a Closed Thermodynamic System?

[heusdens]

second law & universe

Is the universe a closed thermodynamic system, as defined in the laws of thermodynamics?

Some argue it is, or state it is, based on the fact that the universe is by definition everything there is, so it can't really be in thermal contact with anything else as itself.

Can a closed thermodynamic system conserve it's entropy?

If we apply the second law, this would be a borderline, since the 2nd law states that the entropy can not decrease.

Can it be that the universe increases it's entropy indefinately?

I don't see how that can be true, unless for a finite subsystem of the universe of any size.

Because if it did, how to explain that the universe still has useuable energy left?

Some argue then that the universe had a begin, but such can not be conceived of. A universe can not pop into existence from nothing, and this would also break the first law.

Can an infinite system be a closed thermodynamic system?

Since the second law is applyable to finite systems only, we can not state that immediately.
The way we could conceive of the universe as a closed thermodynamic system is to start with a known finite and closed TD system, and add to that a surrounding part, which still match a closed TD system, and repeat that until we cover all of the universe.
But since the universe is probably infinite, we could never conceive of it as a closed TD system.

Conclusion:

The universe in total conserves the amount of entropy (wether or not the universe is a closed TD system or not, and wether the term open or closed are applicable to the universe, or not)

 

[Tyger]

The universe is a closed system in the sense that it is self contained, but it is expanding so that more and more states are made available to the particles in it, so it definitely isn't closed in the thermodynamic sense.

 

[heusdens]

Originally posted by Tyger
The universe is a closed system in the sense that it is self contained, but it is expanding so that more and more states are made available to the particles in it, so it definitely isn't closed in the thermodynamic sense.

The first one I agree with: the universe is all there is.

The second one, I would hold only to be valid for the observable universe, although there is probably much more universe outside of what we observe. Even so, we can not state more then that the universe is locally expanding, but can't know if that is an overall feature of the universe.

If cosmic inflation theory is right, our whole concept of universe would shift.

And the last remark is a sharp argument.

One often hears this used as an argument against an infinite universe, since that would mean the universe already suffered heat death.

I hold it the universe in total must CONSERVE the amount of entropy,

 

[elas]

You are thinking in terms that are to small and then listing all the problems that come from thinking to small.
How can the universe exist as a separate entity? it is an integral part of infinity. Think of the abandoned Steady State theory and replace galaxies with universes and you will be able to visualise the commings and goings of infinity. The only true steady state is infinity itself, in that the fundamental force of infinity is both infinite and constant. Local variations in the force allow creation to occur, but each creation is a temporary event and an increase in force in one area causes a decrease in force in another area these actions can be attributed to the inability of infinity to reach a rest state. Our universe is spreading out and therefore the force per unit of volume is decreasing, but this very act allows the concentration of force in some other part of infiinty the only constant is the total force.

 

[heusdens]

Elas:

I agree with you. The universe is an infinite system.
The term "constant" is, in respect to infinity, some strange phenomena, since a line of infinite length could be shortened or enlarged with an infinite measure and still be infinite.

It was not my own argument to state that the universe is a closed TD system, but this argument is thrown into the discussion often.

My argument is that the universe is NOT a closed TD system (since closed in relation to TD applies only to finite systems).

 

[Neo]

I think the universe is closed because it is by definition self-contained. For a mathematical example, take a set of numbers (all fractions between zero and one). The set is finite since it can be defined and delimited - the set itself is not infinite as not all numbers match the characteristics; however, simultaneously, the amount of numbers contained within the set is infinite.

Imagine space-time to be a subset of consciousness relative to yourself and consciousness a subset of space-time relative to the universe at large. The universe could be a set correspondent to the aforementioned set of fractions; that is to say, it could possibly possesses infinite *variety* within a finite domain, so-to-speak.

 

[elas]

There is a report on the science page of the London 'Daily Telegraph' dated 13 Aug 2003, that the latest observations (by Boomerang and Maxima high altitude balloons), confirms that thr universe obeys Euclidean geometry.
This is precisely what would be expected in a universe controlled by a single (vacuum) force. This strengthens the proposals put forward on my website that the universe is capable of a far simpler explanation than that used at present.