Jump to content


Photo
- - - - -

Is the universe a closed or open system?


  • Please log in to reply
8 replies to this topic

#1 Alan McDougall

Alan McDougall

    Quark

  • Senior Members
  • 689 posts
  • LocationSouth Africa Johannesburg/Sunninghill

Posted 14 August 2012 - 06:56 PM

I know that the universe is open, if it is affected by something outside of it. If there is no outside of it then obviously it is a closed system. I think most people define "universe" in terms that require it to be a "closed system".

I know the answer is probably "closed". The reason I asked is because I want to know whether the law of conservation of energy and similar laws apply in both systems. An open system might have energy added to it or subtracted from it by an external source/sink of energy. If the universe isn't connected to anything else, must I definite the word "universe" TO include everything that could possibly affect anything, Thus, there's no reason laws of thermodynamics wouldn't apply in both closed or open systems?.

In an open system could entropy flow forever and anything that could happen might happen , if this is pseudo science please disregard this comment.


Of course there is also isolated systems but lets leave that out.
  • 0

"Do you know what you do not know?
 

The cat killed curiousity

 

Lets keep it friendly and polite!

Alan McDougall


#2 Greg H.

Greg H.

    Protist

  • Senior Members
  • 941 posts
  • LocationDSM, IA

Posted 14 August 2012 - 07:05 PM

I think the short answer we really don't know but we assume it's closed because we don't have any evidence there exists something outside the universe for it to open onto.

And the laws of thermodynamics do apply in closed and open system. Why would you think they wouldn't?
  • 0

Religion is about belief regardless of the facts and science is about the facts regardless of belief.

To be fair, bananas are like 90% horse.

Remember - if the predictions of your theory disagree with reality, it is not reality that is wrong.

#3 MigL

MigL

    Protist

  • Senior Members
  • 968 posts
  • LocationSt. Catharines, Ontario, Canada

Posted 14 August 2012 - 09:44 PM

Noether's theorem implies that any boundary ( ie. an asymmetry ) in time, linear translation and angular translation, means that conservation laws of mass-energy, linear momentum and angular momentum respectively, are violated at those boundaries.
  • 0

#4 occam

occam

    Quark

  • Senior Members
  • 44 posts

Posted 22 August 2012 - 07:49 PM

Actually it must be cyclic.

If you look at Isotopes, there are a finite number which are "stable"

Therefore if Entropy takes its course, and all the stars are burnt out, and all the possible isotope decays take place, then all we are left with is the stable particles.

The only force left is gravity.

These Isotopes, by definition, are irreducible, so what we are left with is an implosion, which collapses the particles to (presumably) the Planck density.

Where (and I speculate) we get a "big bang" reversal, which generates a new universe.

Chew on that

Occam
  • 0

#5 studiot

studiot

    Primate

  • Senior Members
  • 2,932 posts

Posted 22 August 2012 - 07:51 PM

Before you ask this question you should ask

"Is the universe finite or infinite"

since the terms only have meaning and validity in finite systems.

Edited by studiot, 22 August 2012 - 09:52 PM.

  • 0

#6 zapatos

zapatos

    Lepton

  • Senior Members
  • 1,795 posts
  • LocationSt. Louis

Posted 22 August 2012 - 08:27 PM

Actually it must be cyclic.

If you look at Isotopes, there are a finite number which are "stable"

Therefore if Entropy takes its course, and all the stars are burnt out, and all the possible isotope decays take place, then all we are left with is the stable particles.

The only force left is gravity.

These Isotopes, by definition, are irreducible, so what we are left with is an implosion, which collapses the particles to (presumably) the Planck density.

Where (and I speculate) we get a "big bang" reversal, which generates a new universe.

Chew on that

Occam


But if the galaxy clusters are moving away from each other at escape velocity or greater, wouldn't they just continue to drift apart?
  • 0
And the Lord spake, saying, "First shalt thou take out the Holy Pin. Then shalt thou count to three, no more, no less. Three shall be the number thou shalt count, and the number of the counting shall be three. Four shalt thou not count, neither count thou two, excepting that thou then proceed to three. Five is right out. Once the number three, being the third number, be reached, then lobbest thou thy Holy Hand Grenade of Antioch towards thy foe, who, being naughty in my sight, shall snuff it. -MP

"As a good christian, I'm always going to disagree with any proof you try to give me." -Peter BE cimp

#7 John Cuthber

John Cuthber

    Chemistry Expert

  • Resident Experts
  • 9,813 posts
  • LocationEngland

Posted 22 August 2012 - 08:31 PM

Actually it must be cyclic.

If you look at Isotopes, there are a finite number which are "stable"

Therefore if Entropy takes its course, and all the stars are burnt out, and all the possible isotope decays take place, then all we are left with is the stable particles.

The only force left is gravity.

These Isotopes, by definition, are irreducible, so what we are left with is an implosion, which collapses the particles to (presumably) the Planck density.

Where (and I speculate) we get a "big bang" reversal, which generates a new universe.

Chew on that

Occam

That's proof (of a sort) that it hasn't been round forever because all the unstable isotopes would have decayed.
But it doesn't prove that it's cyclic.
We may or may not get a "Big Crunch" but the isotopes don't tell us what will happen.
  • 0
What's this signature thingy then? Did you know Santa only brings presents to people who click the + sign? -->

#8 Alan McDougall

Alan McDougall

    Quark

  • Senior Members
  • 689 posts
  • LocationSouth Africa Johannesburg/Sunninghill

Posted 23 August 2012 - 09:07 AM

Actually it must be cyclic.

If you look at Isotopes, there are a finite number which are "stable"

Therefore if Entropy takes its course, and all the stars are burnt out, and all the possible isotope decays take place, then all we are left with is the stable particles.

The only force left is gravity.

These Isotopes, by definition, are irreducible, so what we are left with is an implosion, which collapses the particles to (presumably) the Planck density.

Where (and I speculate) we get a "big bang" reversal, which generates a new universe.

Chew on that

Occam


How can gravity exist without mass?
  • 0

"Do you know what you do not know?
 

The cat killed curiousity

 

Lets keep it friendly and polite!

Alan McDougall


#9 JohnStu

JohnStu

    Atom

  • Senior Members
  • 262 posts
  • LocationCanada

Posted 18 September 2012 - 01:03 AM

The universe cannot be an open nor a closed system. One can create a closed or an open system within the universe.
  • 0




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users