[tex]\rho[/tex] is the density of phantom energy. tBR is the time of the Big Rip. t is the cosmic time, so introducing any cosmic time that you want in the formula, you get the density of phantom energy at that timeI'm sorry, however I am still confused as to how the dark energy gains energy. The forumla contained time and density. I'm not sure how they are related though
Is it because matter is being turned into energy and therefore, the there is more dark energy and less gravatational pull from matter? How would one calculate how much mass there was in the universe?
You know...the first milliseconds of the big bang was in violation of the weak, strong and dominant forces. Maybe, this is like similar to a mini-big bang. Let's say a super massive black hole underwent a "big bang" of its own. Releasing great amounts of energy causing an unequal expansion of the universe. That energy is now called dark energy and is the cause of the isotropic universal expansion.meteor said:As I said, I would not be very worried about phantom energy. I think that dark energy will result to be a cosmological constant or perhaps quintessence. Phantom energy requires very strange things: violation of the weak, strong and dominant energy conditions, and also superluminal sound speed. (BTW, Somebody knows why requires superluminal sound speed?)
UrbanXrisis said:You know...the first milliseconds of the big bang was in violation of the weak, strong and dominant forces. Maybe, this is like similar to a mini-big bang. Let's say a super massive black hole underwent a "big bang" of its own. Releasing great amounts of energy causing an unequal expansion of the universe. That energy is now called dark energy and is the cause of the isotropic universal expansion.
Just a moment. Correct me if I'm wrong ( I most likely am wrong). But perhaps there is a discrepancy in the way the Cosmological Constant is measured and how it is calculated with QFT. It would "seem" that the CC is being measured in the past as we examine the distant past. But the calculated CC using QFT would produce the present value. Perhaps the calculated CC is 120 OOM more than observed value because the CC was 120 OOM less in the past than it is right now. We already know that the distant past shows a deceleration but the present universe is accelerating instead.Chronos said:One way to look at expansion is attributing it to the vacuum energy density. ZPF energy still hovers as a suspect on the cosmology radar. The confounding thing about ZPF energy is it seems far too high in theory - about 120 OOM as others have mentioned. The measured value is, however, quite small [by measured I mean the observed flatness of spacetime geometry as determined by the WMAP survey, among others]. In that case, it makes sense that expansion accelerates as the vacuum between islands of matter [galaxies et al] increases in volume. The repulsive force of expansion is far weaker than even gravity, but over cosmological distances, it is sufficient to fuel expansion.
The discrepancy often quoted as 120 OOM is not a time-dependant one. QFT says that the energy of the quantum vacuum is VERY large (summing over all possible frequencies). The "flatness" of our universe as seen in GR seems to rule out these huge energies, since mass/energy equivalence should give these tremendous energies a huge gravitational effect.Mike2 said:Just a moment. Correct me if I'm wrong ( I most likely am wrong). But perhaps there is a discrepancy in the way the Cosmological Constant is measured and how it is calculated with QFT. It would "seem" that the CC is being measured in the past as we examine the distant past. But the calculated CC using QFT would produce the present value. Perhaps the calculated CC is 120 OOM more than observed value because the CC was 120 OOM less in the past than it is right now. We already know that the distant past shows a deceleration but the present universe is accelerating instead.
UrbanXrisis said:How solid is the theory of the Big Crunch?
This is very true, we need to look at our present situation because our current situation is more important than what will happen in billions of years. However, if in about 60 Billion years, our universe will end in a big crush and we will all be a singularity, or, everything will freeze dude to heat death, woudn't someone like a more "happy" ending? I mean, what's the point of human's existence when in 60 billion years, the WHOLE UNIVERSE will be "dead." Is there any "happy" theories out there? Einstein thought that the universe was stable and not explanding before Huble confirmed that it was turly expanding. Einstein's "biggest blunder of his life" might be the most "optimistic" one yet. Sure, there's theories that the universe will just rip into 'sub-universes' and such but what impact will that have on life? And these sub-universes will all die due to heat death. What is the purpose of life when in the end, everything will be "dead." Is there any meaning in life as a whole? Is there any meaning to the life of the universe?marcus said:I think it is about as solid as that froth on top of a capucino that they sprinkle the powder cocoa on.
or a marshmallow that you are toasting, just before it falls off the stick.
People who try to think seriously about the more likely way-future scenarios usually assume that it keeps expanding indefinitely and gradually getting colder and darker----and stars burn dimmer and go out----and more lonely as things keep getting farther apart.
selfAdjoint image about the last species turning out the light is perfect!
But also, as Nereid suggests, nobody should believe any of this because it is all theorizing and the actual future could turn out anything including totally unexpected.
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hey people! let's not worry about the UNIVERSE for goodness sake, let's worry about the Sun!
I read recently that it is due to get about 10 percent hotter over the next 4 billion years. Can't remember exactly. Does anyone recall?
The Universe is probably good for at least another 60 billion years if we can just find a way to keep warm. But we have an immediate problem with our own planet! And the solar system is going to develop problems, or else need extensive work, just to keep it comfortable in only a couple of billion years.
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Maybe the yearend Solstice is a good time to think about the future of life and the solar system----I don't know about that, but maybe it is.
My person suspicion is (first of all we really don't know yet) but, if humans can restrain themselves from gutting, overpopulating, and trashing their own planet, they will find some way to go on indefinitely until some more talented and entertaining species replaces them---or even just one with slightly better table manners.