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Brian Albin
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Reged: 08/22/06

Loc: Western Oregon
Is Energy Increasing in the Universe? new
      #5761672 - 03/28/13 01:44 AM

As the Universe expands, is the amount of energy in the Universe also increasing?
If it is not, Is this decrease in specific energy per unit of space volume occurring by there being ever fewer atoms in each cubic foot of space? Or are there as many atoms per unit volume as ever, but each proton and electron are not as powerful as protons and electrons once were?

An experiment to measure flux density [if that is the correct labeling] would be a problem because we could not know if we were measuring typical space or an eddy of locally lesser or greater than usual energy density.


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neotesla
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Reged: 11/18/10

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Re: Is Energy Increasing in the Universe? new [Re: Brian Albin]
      #5762259 - 03/28/13 11:56 AM

You cannot create energy, well I suppose you can if you can convert mass...

Assuming the big bang is real, the energy released then is the sum total and is being dispersed along with the mass, how would energy increase? Entropy decreases until a static state is achieved.


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Carl Coker
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Reged: 07/30/12

Loc: Ohio
Re: Is Energy Increasing in the Universe? new [Re: neotesla]
      #5762653 - 03/28/13 04:16 PM

GR does not respect global conservation of energy. As the universe expands, more dark energy is created, and the energy content (though not the energy density) of the universe increases.

If dark energy is a cosmological constant, the energy density of the universe will asymptote to the current density of dark energy, while the total energy content of the universe increases without bound.


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neotesla
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Re: Is Energy Increasing in the Universe? new [Re: Carl Coker]
      #5763143 - 03/28/13 08:40 PM

Care to cite a reference to support this? Otherwise, dark energy would be the new pixie dust...

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EJN
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Reged: 11/01/05

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Re: Is Energy Increasing in the Universe? new [Re: neotesla]
      #5763216 - 03/28/13 09:26 PM

Quote:

Care to cite a reference to support this? Otherwise, dark energy would be the new pixie dust...




http://en.wikipedia.org/wiki/Big_Rip

Complete with equations!


Dark energy aside, energy is not conserved globally in general relativity
in any non-static spacetime because the covariant derivative of the
energy-momentum tensor is not zero.


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neotesla
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Re: Is Energy Increasing in the Universe? new [Re: EJN]
      #5763242 - 03/28/13 09:42 PM

All of that is dependent on an hypothetical phantom energy... the even more elusive pixie dust...

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Jarad
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Reged: 04/28/03

Loc: Atlanta, GA
Re: Is Energy Increasing in the Universe? new [Re: neotesla]
      #5763811 - 03/29/13 08:05 AM

At the moment, dark energy is a hypothesis created to explain the observation that the expansion of the universe is accellerating. It has not been directly confirmed by other methods yet.

But it's not "pixie dust", it is a rigorous hypothesis that does explain real observations. There are some other possible explanations, but none of them have been confirmed, either.

So I would answer the OP's question with "If the dark energy hypothesis is correct, then energy is indeed increasing as the universe expands. But we aren't sure yet."

Jarad


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neotesla
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Re: Is Energy Increasing in the Universe? new [Re: Jarad]
      #5764155 - 03/29/13 10:36 AM

My point is that for a theory to based on a hypothesis, and extrapolating further to speculate a even more remote possibility of a rarer form of dark matter can contribute to the Big Rip, makes this border on the realm of fantasy. Especially if there is still no definitive proof of the existance of the original premise. This borders on existentialism, arguing about the possibility of existance from different reference points.

Rigorous of not, there is still no conclusive evidence of the presence of dark matter or dark energy, it make things look good in terms of explaining expansion, but is it still not proven.


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CounterWeight
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Re: Is Energy Increasing in the Universe? new [Re: neotesla]
      #5764184 - 03/29/13 10:46 AM

I think if you look at discussion about de Sitter and Lemaitre the case of dark matter is made sufficiently? I just posted two or 3 links in the other thread about expansion... at least I think that is what it was about...

post thought edit... there is also that thing about the second law of thermodynamcis... which can lead you to conservation of energy.

or sort of... maybe?


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Brian Albin
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Reged: 08/22/06

Loc: Western Oregon
Re: Is Energy Increasing in the Universe? new [Re: CounterWeight]
      #5765545 - 03/29/13 07:02 PM

I have a one hundred year old anvil out in the shop. It is marked as weighing 70 lbs. Does it still weigh 70 lbs today? That is to say: Does it contain as many atoms now as when it was made? I am not asking about loss due to abrasion, but a hypothetical anvil.

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neotesla
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Re: Is Energy Increasing in the Universe? new [Re: Brian Albin]
      #5766339 - 03/30/13 09:14 AM

Are you are asking whether matter dissintegrates over time? It can, but nothing in your life time, or even in the earth's life time. Proton life time is >2.1×10^29 years (stable)

http://en.wikipedia.org/wiki/Proton


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Brian Albin
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Reged: 08/22/06

Loc: Western Oregon
Re: Is Energy Increasing in the Universe? new [Re: neotesla]
      #5768164 - 03/31/13 07:44 AM

So it seems there is quite a steady state in any piece of matter currently in existence.
Thanks, New Tesla.


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Napersky
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Re: Is Energy Increasing in the Universe? [Re: Brian Albin]
      #5768773 - 03/31/13 01:10 PM

According to Stanford String Theorist Dr. Andrie Linde the Universe is expanding, energy is increasing, the energy density is remaining the same, per his inflationary theory. The vacuum has "Heavy Nothing" (which is not science fiction he said) the energy density remains the same with the continued expansion of the universe.

See Stoneybrook video at 28 minutes:

http://scgp.stonybrook.edu/archives/6579


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