How Will the Universe End? Big Crunch Theory

[turbo]

This is assumes that the "dark energy" that is invoked to explain the accelerating universe becomes predominant, not only at cosmological scales but atomic ones as well.

According to meteor "It seems like good news", I cannot understand how!

Garth

I think he was saying that Gravitational Back Reaction (negating the Big Rip) was good news, but since none of us are going to live past the next 100 years or so, much less live out the cosmos, I can't see how it is good or bad news either way. Now if a white dwarf not too far from the Sun managed to accrete enough mass to enter the electron degeneracy stage, or if a large asteroid or comet managed to score a hit on our little planet, we would be toast. As it stands, though, our Sun will go red giant and cook all life on Earth eons before the Big Rip gets a shot at us. In more practical terms, if we don't smarten up, we will probably kill ourselves by imbalancing and poisoning our environment before the cosmos even gets a fair chance to take us out.

 

[meteor]

I think he was saying that Gravitational Back Reaction (negating the Big Rip) was good news,

True. The idea of Phantom energy was proposed in this paper
http://arxiv.org/abs/astro-ph/9908168
then later, it was found that Phantom energy would lead to a Big Rip, aka Cosmic doomsday. According to astro-ph/0302506, with a Hubble constant H=70 km/s/Mpc and a dark energy equation of state w=-3/2, this Big Rip will occur in 22 Gyr. That's too bad, but Wu and Yu paper gives new hope to everyone that is fearing the Rip.

I can't see how it is good or bad news either way

We are surely fried anyway, you are true, but it's not good to thow the towel so soon. We as humans have achieved great feats, don't understimate the capability of human intelligence. Who knows what we are capable to do

 

[meteor]

Does this mean that the universe will expand too fast that it will just rip itself? how is it possible to tear all matter apart?

It's because dark energy, contrarily to the ordinary matter that we are used to, exerts negative pressure, that is, tries to separate things, is a kind of antigravity. It would be OK if it would not be the case that Phantom energy is a kind of dark energy that has the property that its energy density increases with time. The matter of the fact then, is that its power is increasing, so there's a moment that it really rips all known structure, that's the Big Rip. In Phantom Cosmology, the end of time will occur in the Big Rip singularity, it will occur 22 Gyr from now with the parameters of my previous post. But some structures will be torn apart a bit before. For example, according to
http://arxiv.org/abs/astro-ph/0302506
with the parameters indicated, the Milky Way will be stripped 60 million years before the Big Rip singularity

Just to dissipate the gloomy tone that my last posts have acquired, I'll say that I'm not very worried about the Big Rip, because phantom energy is not the only candidate to dark energy. Other candidates are the cosmological constant, and a scalar field called quintessence. In these models there's no Big Rip.

 

[UrbanXrisis]

energy density increases with time

How does it increase in energy? Or do we not know that yet. Also, since the universe is accelerating in expansion, is this why theorists have concluded on the existence on this Phantom energy?

 

[meteor]

How does it increase in energy?

Good question. Do you have any idea? Look formula 4 of this paper. It gives the density of phantom energy as a function of time...
http://arxiv.org/abs/astro-ph/0407048

 

[UrbanXrisis]

Thanks for the reference, I don't understand what any of the symbols mean except for t=time. rho=? n=?

By the way, in that article, they talked about the 'big smash.' How is that different from the big crunch?

 

[meteor]

Big Smash is a idea proposed by McInnes. Is a variation of the Big Rip idea. In big Rip the universe is destroyed. In the Big Smash is broken into disconnected pieces

 

[UrbanXrisis]

I'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? How could one calculate the amound of mass that has turned into energy?

 

[meteor]

Hi, what's the weather in Alaska?

I'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

\rho is the density of phantom energy. t_BR 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 time
However, it would be nice if somebody can explain what's \rho_{eq} in formula 4, because in the text is not explained what is. I guess that it refers to the density of the energy of matter when it equals the density of phantom energy. Well, I'm used that a lot of papers don't explain some of their expressions in their formulas...

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?

This is an interesting idea, but I have not seen any paper that suggests that matter is being turned into phantom energy. You have a series of laws and they just give you the raw facts. Sometimes the laws don't explain you why things happen, just howhappen. then we must question ourselves: so why these laws model so well our physical environtment? It's possible that all that can we ever obtain are the laws and not the reason behind them? Well...

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]

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?)

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.

 

[UrbanXrisis]

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.

Any ideas? Is it possible that the jolts of energy are formed from a super massive black hole that consumed too much mass and ignited energy from all its mass? (E=mc^2 since mass and energy are interchangeable) This obviously happened millions of years ago so that we only see the effects of this release in what is now called 'dark energy'

 

[Chronos]

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.

 

[Mike2]

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.

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.

 

[turbo]

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.

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.

I believe that quantuum gravity will eventually sort this out, and the key will come from a proper understanding of the virtual particles of the ZPE EM field. In my model, the ZPE field is neutral and non-attractive in the absence of polarizing mass, but becomes polarized in the presence of mass due to a differential in the matter/antimatter infall rate (experimental verification or falsification in our lifetimes, hopefully). Interaction of matter with these virtual fields is the source of gravity and inertia. If gravity is indeed the local effect of mass interacting with polarized ZPE fields, and NOT GR "curvature of space-time", we get rid of gravitons, Higgs bosons, force acting over a distance, etc, and we have a very good reason why the ZPE fields in "empty' space (in the absence of nearby polarizing matter) will NOT gravitate and cause the universe to collapse.

 

[Nereid]

Back to the original question - an interesting exercise is to draw up a list of answers to the question 'how will it end?' ... by time (recorded homo sap. time, esp 20th and 21st century). Now, given how tiny a fraction even one century is of the life of the universe to date, who would like to speculate how the answer will evolve, over the next century?

 

[selfAdjoint]

Will the last species to perish please turn out the lights?

 

[marcus]

How solid is the theory of the Big Crunch?

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.
========
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.

======
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.

 

[UrbanXrisis]

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.
========
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.

======
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.

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?