Primordial inflation explains why the universe is accelerating today

[Qfwfq]

http://www.arxiv.org/abs/hep-th/0503117

 

We propose an explanation for the present accelerated expansion of the universe that does not invoke dark energy or a modification of gravity and is firmly rooted in inflationary cosmology.

The accelerated expansion is usually interpreted as evidence either for a “dark energy” (DE) component to the mass-energy density of the universe or a modification of gravity at large distance. The goal of this Letter is to provide an alternative explanation for the ongoing phase of accelerated expansion that is, we believe, rather conservative and firmly rooted in inflationary cosmology.

This letter seems to be striking up a bit of noise in cosmology circles according to a friend of mine.

[Jay-qu]

Yeah, well it should rouse some controversy. There are still many people that support the idea of a closed universe (expansion reverses to the big crunch). I myself recognise the idea of an open universe that will contiue to exand indefinitly, but to what velocity will this acceleration tend towards eventually -> c ... then things will get interesting

NOTE:: The expansion isnt the spreading out of the universe (like dropping a whole lot of marbles and watching them roll away from each other) but it is the space itself that is doing the expanding!

[The D.S.]

an intriguing idea, one that makes sense too ;)

[lindagarrette]

So what is the difference between this theory and the "Big Rip?" (The universe is dissipating at an increasing rate so that eventually there will be only cold, motionless space, virtually nothing left.)

[TeleMad]

... but to what velocity will this acceleration tend towards eventually -> c ... then things will get interesting

 

There are already galaxies receding from us (and vice versa) superluminally.

[Bo]

So what is the difference between this theory and the "Big Rip?"

 

There is none ;)

this theory doesn't predict anything new, it only gives a new explaination as for why our current univers is expanding that fast. and it is quite an interesting idea they have.

 

Bo

[Qfwfq]

Another friend of mine, who graduated in cosmological stuff, produced a picture after reading this article. One of the authors liked the picture quite a lot.

[Aki]

No matter if the universe continues to expand forever, or if it stops expanding and contract to a big crunch, our universe will one day die. If there isn't a big crunch, then entropy will take over, and nothing would exist.

[Qfwfq]

...and nothing would exist.

Matter and energy would still exist, only gray, gray, gray, gray......

[OmegaX7]

;) You put forth one of several theorys. I think your on the right track. This is a widely speculative point in time though. No one can say for sure (yet) whether we're expanding, static, or contracting. Isn't this "Lamba" we're talking about? It's likely that we are here (at this point in spacetime) approxamately at the midpoint in our universal development. Since gravity is a universal force theres no reason to think that even if we "do" contract the gravitational force will not pull those escaping galaxys right back. And thats entirely theoritical as well. "I", personally, consider the fact that all mass can be converted to energy. That said, we know that there is a limited supply of energy in the universe. After the Big Bang the stage was set. No more energy will ever be created or destroyed again untill this reaction runs it's course. ;) "Energy can be tied up "in mass" - Energy must propogate." The galaxys that are receading faster than "c" still poccess their respective gravitational fields and so must have some part in pulling more matieral out after them. This may have some effect on the "red shift" as well, and therefore being deceptive in distance. ;) As you can see, there are more things to be considered than you could "shake the proverbial stick at." More to the point on your original question. The speed of expotential expansion of energy/mass during the first second of exsistance was (had to be) well beyond "c"; after all, there wasn't anything to be pushed out of the way, right? And outside our expanding sphere there remains nothing, so whats "in the way" of the stuff at the outermost regions to slow things down?? Now, the only gravity that matters in within this sphere of ours and nowhere else. Gravity propogates at "c" but gravity is a result of the presence of mass. In the very early universe the proportion of mass to energy was surely different and energy can travel a lot faster without baggage in the form of mass. Theres too much here to keep correllated (straight). "ENERGY" - - energy "cannot" be destroyed, "that must remain paramount". "If" the cyclic theory proves out, then that in itself would explain "eternity" and solve the beginning & end problem. Still doesn't solve the god thing though. "If" theres an end, that means theres a definit beginning, and "that" remains quite an issue as yet. And what about the Black Holes that seem to be getting discovered at the center of each solar system ;) ; even our own is under scrutiny at the time but we have too much local dust and such in the way. These "may be" providing the dynamic energy that is driving the entire universe by converting mass back into usable energy. ;)

You question is multi-faceted and at the fore front of our research.

And finally, to address your opening statement, heck, I don't know!

As youv'e noticed this is mostly phrased in thoughts and statements. Thats about the way I think as well.

L8R - - - OmegaX7

"After all is said and done, Gravity Rules."