Universal Darkness?

[Murasame]

Anyone have any sites or articles about this theory, even though its not really a theory more of something derived from formulas! (i dont even know if this really exists its just something i came up with the other day and the fact its so simple it must have been said before)

So basically my idea was if no energy can every be created and none can ever be destroyed, and the universe is constantly expanding, will that not mean that over an extended period of time say 20 billion years, the same amount of energy in our universe today will be spread across the much larger universe, therefore decreasing the amount of energy in any one given place that exists now! Taking this into account, all suns come to an end right? whether they reach supernova or black holes or wotever, and their energy gets dissapted outwards in a big explosion, will there not come a time where energy is so far apart that jeans standard mass can never be met, therefore there will never be enough gas in any one given place to form a sun, therefore making the universe black permantly!

(btw i havent really factored in how dark matter would effect any of this, or the fact that universe might stop expanding, but u get the drift)

[Pulse]

Well perhaps energy is needed to make the universe expand or something. . . There is a theory though that if the universe keeps expanding it will just tear its self apart anyway :P

[Bilbo Fraggins]

What if there's an infinite amount of energy and this 'unable to create or destroy' assumption is just used locally?

And anyway, in 20 billion years time the universe will be contracting again and it will get a little brighter :P

[the funkmaster]

Indeed, just like the idea of increasing entropy, the rules are different for closed and open spaces :)

[Baby Bear]

Your definition of black only corresponds to the energy that your eyes see in the visible wavelength, the universe would still be "bright" with the other wavelengths.

[Hotel2Tango]

You are right Murasame, it has been thought up before. As soon as Hubble discovered the red-shift of galaxies moving away from us people realised that one possible future could be expansion for ever and evertually 'darkness'.

[Murasame]

Your definition of black only corresponds to the energy that your eyes see in the visible wavelength, the universe would still be "bright" with the other wavelengths.

If you merge into the dark matter arguement that it is causing an increasing speed of universal expansion, this shows that there is actually more negative matter repelling the universe outwards as opposed to positive energy pulling it in, the universe will expand until all the dark matter has reached a high energy level for there to be a more than 50/50 split of dark/positive matter! until this happens, if the above is correct, the universe shall actually keep on expanding! and matter will appear much more sparadically! And not only will light energy get darker and darker but all forms of energy will do as well, so in theory everything will tend to shift to the lower end of its respective spectrum and therefore and increase in lower spectra energies!

[[n00b].eesh.]

My personal idea is that the expansion is just one part of a continuous cycle of expanson/contraction that keeps on renewing the universe. This theory is based on no evidence what soever but I think is quite fun! :D

[Lungboy]

I think the theory that says the universe will keep expanding until there is infinite distance between every particle has its merits. As far as i know Bilbo, current thinking is that the universe will not start contracting again.

[Murasame]

Yea i always do think that, with my whole 50/50 dark/positive energy thing, when there is evetually more positive energy the universe wil lcontract! One thing that interests me, will time start to reverse when the universe starts collapsing? I think its a very interesting idea

[Beef~]

i suspect you're actually talking about the 2nd law of thermodynamics which states "In any cyclic process the entropy will either increase or remain the same."

entropy is a characteristic measure of the chaotic nature of molecules. Our universe is an irreversible system which means that entropy is always increasing. Eventually given enough time all the energy in the universe will tend to become equalized with energy spread out in the surroundings and unable to be used for things like light and heat so yes in the end it will be completely dark.

[Murasame]

yes i was basing my theory on the second law of thermodynamics, but would universal collapse go against this law? or would all the matter in the universe in a small place have a higher entropy?

[Beef~]

some people have speculated that if the universe was to collapse under the magnitude of its own gravity then time might start passing in reverse and thus lower entropy meaning everything becoems more and more ordered and concentrated till a singularity is formed (may be possible to destroy energy in a singularity as the usual laws of physics no longer hold). as far as i'm aware its not possible to lower entropy in any other way. for example when you cycle a bike some of the energy is lost as heat and sound which can never be used again by anything - resulting in increased entropy. only reversible adiabatic processes may be isotropic (constant entropy) although i don't beleive there is such a real a thing in existance but theoretically its possible to design a system whereby no entropy is gained and thats about the best we can do. consider putting some books at the top of a shelf, given enough time the books will eventually fall off and be disordered and chaotic on the floor. thats entropy but if you try to reorganize them back at the top you will use more energy in raising the books' potential causing even more disordered energy than providing order. as time tends to infinity this is a net increase of entropy and eventually all forms of usable ordered energy will be used and the books will fall back down.

[Murasame]

i've heard that analogy before, brief history of time?

[Beef~]

yeah i think so. hawking is very good at drawing analogies.

[Lord Fondlemaid]

Stephen Baxter's book "Deep Future" offers a well informed and interesting view on this subject. Baxter is a scientist himself I believe, who has used his scientific knowledge as the basis for his sci-fi novels.

Read it!

[Majestic]

Well, we've always got the collision with the Andromeda galaxy to consider first. Knowing our luck, we'd probably collide with another body :P

While I'm on the subject.. http://space.com/scienceastronomy/sun_planets_041201.html

[Hotel2Tango]

I think chances are we wont hit anything else if our galaxy hits another, interstella distances are just so unimaginably vast.

Stephen Baxter is pretty good. I have only read one of his about evolution. Very good. A series of stories starting with some rodenty mousey thing that survives the KT boundary meteor impact that wiped out the dinosaurs and manages to breed. Then onwards through time, short stories about key points in human evolution. very good, but it gets a bit bleak when he starts talking about evolution after humans have been wiped out.

[Majestic]

Yeah, It was sarcasm (hence the smiley) :)