death of universe

[jagadish]

this is with reference from Natgeotv " In the farthest reaches of space, a volatile battle is taking place between two forces so great, they may eventually destroy the very universe itself. Known as Dark Matter and Dark Energy, these opposing forces have the capacity to rip apart the universe atom-by-atom. While scientists have previously theorised about a “Big Crunch” where the universe retracts back to its original size, the discovery of Dark Matter and Dark Energy has placed that hypothesis on the backburner. Some astronomers now believe that if Dark Matter offsets Dark Energy then as the universe slowly expands, stars will gradually fade, running out of fuel and leading to a dark, cold and lifeless universe. Others hypothesise a much more violent end where Dark Energy continues to expand the universe at a greater and greater speed. Stronger than gravity, Dark Energy would pull apart everything down to the fundamental particles – the universe’s very fibres. While the universe’s end may be 50 billion years away, great leaps in science will continue to alter how we believe the universe was formed – and how it will end."
regular matter only accounts for 4% of the Universe. The other 96% - dark matter and dark energy - is a total mystery.we are trying to trace out something which ha no direct evidence however since every beginning has an end i think by the time we know the beginning (big bang theory):naughty we can also trace out its end

[Tormod]

Understanding the beginning does not mean we would know the end. In the book the Five Ages of the Universe, the authors state a case for a universe which lives on for trillions of years, so long that even the fundamental particles completely decay.

Dark matter has been mapped:
BBC NEWS | Science/Nature | Hubble makes 3D dark matter map

But I do agree - these are mysteries we need to study and find good answers to. We may not really know the right questions yet.

[sanctus]

You also have to remeber that the expansion is seen on big scales, the distance earth-sun is not increasing.... What seems more likely with dark energy taking iver is that we will not see anymore any other galaxy one day (I got this theory from Science or another like journal).

[Moontanman]

Check out this news article, it has a new take on the problem.

http://hypography.com/forums/news-in...ve-us-our.html

[jagadish]

intersting indeed if fundamental particles completely decay then we would expect the universe to be viod,the big bang states that after expanding the universe contracts to ite initial form i.e dense massof energy

[Jim Colyer]

I find it hard to believe that the universe will die. The fact that it came into existence to begin with leads me to feel this way. To exist at all, is to exist forever in one form or another. Maybe this is "faith." But what is the alternative to faith? No faith? Where does that lead?

[CraigD]

Originally Posted by jagadish

the big bang states that after expanding the universe contracts to ite initial form i.e dense massof energy

The currently accepted Big Bang theory does not state that the currently observed expansion of the universe will be followed by contraction into a “big crunch” or “big bounce”. These speculative versions of the theory were taken seriously early in its history, ca. the 1930s and 40s, but subsequent observation has decreased the estimated likelihood of their being correct to effectively (but not certainly) zero.

Originally Posted by Jim Colyer

I find it hard to believe that the universe will die. The fact that it came into existence to begin with leads me to feel this way.

One’s understanding of the meaning of the phrase “death of the universe” is aided, I think, by defining it’s metaphorical language in more precise scientific terms, and exploring current scientific thinking of these more precise ideas.

IMHO, a reasonable definition of a “dead universe” is one with no phenomena in it that we would consider alive. We can be very liberal in defining “alive”, including the most simple imaginable biological life, hypothetical non-biological life such as organized collections of magnetically bound plasma in stars, and self maintaining and replicating machines (ie: Von Neumann machines).

All of these “life forms” have in common the need for energy, as they all must do mechanical work to “live”. Effectively, energy in our universe comes in a few forms:

• differences in heat in neighboring volumes of space;
• the conversion of mater to energy via nuclear fusion, which occurs mainly in stars;
• the conversion of mater to energy via nuclear fission, which occurs in decaying radioactive elements

To the best of our scientific understanding, all of these processes will eventually end everywhere in the universe. At that time, no matter how well-adapted or designed it is, no “life form” will have energy available to it to do work, so none will be “alive”, and the universe can reasonable be considered “dead”. This universe will not lack energy altogether, but none of it will be in a form usable via any possible means, and will continue expanding until any given volume of it is empty.

Our present-day theoretical understanding of quantum mechanics offers the possibility that this very distant future “dead universe” will not continue indefinitely. One hypothesis for the creation of our current universe is that it arose from a very improbably “quantum fluctuation” in the “primordial vacuum” that preceded it. (this idea, notably described by physicist Edward P. Tryon as “our Universe is simply one of those things that happens from time to time”, has been discussed in various hypography threads, such as here)

Originally Posted by Jim Colyer

But what is the alternative to faith? No faith? Where does that lead?

On the very long time frames discussed in this post, our best science suggests that the ultimate fate of the universe is unaffected by our having or not having “faith”.

In the short term, I can’t describe the consequences of faith or its lack only with some specific examples. Richard Dawkins’s lack of faith results in him writing and promoting books that describe religious faith as delusional and unhealthy, such as “The God Delusion”. Frank Tippler’s IMHO excess of faith lead him to write what many consider among the silliest works of nonfictional popular physics, such as ”The Physics of Immortality”. I’ve countless personal anecdotal examples of people who describe themselves as having much faith, and people who describe themselves as having none, who all appear about equal in civility, trustworthiness, and social worth.

[HydrogenBond]

I am not sure what it is called, but I think Einstein said if one was to travel into space one would eventually return to where they began in sort of a loop. Does this mean that the universe will loop, returning by default?

[CraigD]

Originally Posted by HydrogenBond

I am not sure what it is called, but I think Einstein said if one was to travel into space one would eventually return to where they began in sort of a loop. Does this mean that the universe will loop, returning by default?

Though I can’t recall a specific mention of Einstein of the idea that space “loops back” on itself (rather like the “space” in video games like Asteroids), it sounds like something he’d say. Einstein liked thinking about geometry, and relating it to the physical universe.

The best discussion of this idea I’ve read was “Is Space Finite” (600 KB PDF) by Jean-Pierre Luminet, Glenn D. Starkman, and Jeffrey R. Weeks, which appeared in the 4/1999 issue of Scientific American. Though very speculative, this article does IMHO an excellent job of presenting the idea’s many complicated (if you’ll pardon the pun) twists and turns, and notes that of myriad hypothetical “wraparound universes”, many are falsifiable via special analysis of telescope data, and names several teams with plans, as of the 4/1999, to conduct such surveys.

In summary, I’d describe the “wraparound universe” as a unlikely, but very interesting hypothesis, well worth study and contemplation regardless of its truth or falsehood.

Care should be taken not to confuse the “wraparound universe” idea with the “cyclic universe” idea. Although both draw from the same theories and observations, they describe completely different hypothetically observable phenomena.