http://en.wikipedia.org/wiki/Future_...nding_universeObservations suggest that the expansion of the universe will continue forever. If so, the universe will cool as it expands, eventually becoming too cold to sustain life. For this reason, this future scenario is popularly called the Big Freeze.
If dark energy—represented by the cosmological constant, a constant energy density filling space homogeneously, or scalar fields, such as quintessence or moduli, dynamic quantities whose energy density can vary in time and space—accelerates the expansion of the universe, the space between clusters of galaxies will grow at an increasing rate. Redshift will stretch ancient, incoming photons (even gamma rays) to undetectably long wavelengths and low energies. Stars are expected to form normally for 1012 to 1014 (1–100 trillion) years, but eventually the supply of gas needed for star formation will be exhausted. And as existing stars run out of fuel and cease to shine, the universe will slowly and inexorably grow darker, one star at a time. According to theories that predict proton decay, the stellar remnants left behind will disappear, leaving behind only black holes, which themselves eventually disappear as they emit Hawking radiation. Ultimately, if the universe reaches a state in which the temperature approaches a uniform value, no further work will be possible, resulting in a final heat death of the universe.
This future history and the timeline below assume the continued expansion of the universe. If the universe begins to recontract, subsequent events in the timeline may not occur because the Big Crunch, the recontraction of the universe into a hot, dense state similar to that after the Big Bang, will supervene.
This had never occurred to me, but apparently in a few trillion years the universe will be a frozen, barren wasteland incapable of sustaining life or even energy, and may eventually collapse in on itself. The universe is believed to only be about 14 billion years old, so relatively speaking we seem to have come along at the near begging of our universe's shelf-life.
More on the Big Crunch:
http://en.wikipedia.org/wiki/Big_CrunchIn physical cosmology, the Big Crunch is one possible scenario for the ultimate fate of the universe, in which the metric expansion of space eventually reverses and the universe recollapses, ultimately ending as a black hole singularity or causing a reformation of the universe starting with another big bang.
If the universe is finite in extent and the cosmological principle (not to be confused with the cosmological constant) does not apply, and the expansion speed does not exceed the escape velocity, then the mutual gravitational attraction of all its matter will eventually cause it to contract. If entropy continues to increase in the contracting phase (see Ergodic hypothesis), the contraction would appear very different from the time reversal of the expansion. While the early universe was highly uniform, a contracting universe would become increasingly clumped. Eventually all matter would collapse into black holes, which would then coalesce producing a unified black hole or Big Crunch singularity.
This could be a topic all itself, but reading about this reminded me of the cyclical Hindu model of the universe so I thought I'd share a bit about that.
http://en.wikipedia.org/wiki/Hindu_c...f_the_universeAccording to Hindu Philosophy, the universe (or multiverse) never came to be at some particular point, but always has been, always will be, but is perpetually in flux. Space and time are of cyclical nature. This universe is simply the current one, which is in flux and constantly changing, when it finally ceases to manifest, a new one will arise.
This is similar to the Cyclical Universe Theory in physical cosmology. The Big Bang is described as the birth of the universe (Brahma), the life of the universe then follows (Vishnu), and the Big Crunch would be described as the destruction of the universe (Shiva).
The ultimate fate of the Universe is still an open question. The final answer depends upon the mass-energy content of the system as a whole. If it is below a certain limit, the Universe shall expand forever. If it exceeds a certain limit, it will contract into what has been conjectured as The Big Crunch.
The Hindu viewpoint of the continuous cycle of creation, destruction and rebirth is attuned to the theory of Big Bang - Expansion - Contraction - Big Crunch. This 'oscillation' is portrayed in Hindu texts, especially in the Bhagwad Gita as Shrishti followed by Vinaash. The period of Vinaash is one of extreme chaos where the very laws of Nature are described to fail. If the Big Crunch happens, the movement of galaxies towards each other will produce very strong gravitational fields which may make relativistic effects perceptible at a great magnitude. The physical phenomena which we are used to may change wildly or be non-existent.
They believed the universe was divided into four epochs of time known as Yugas.
http://en.wikipedia.org/wiki/YugaYuga (Devanāgari: युग) in Hindu philosophy is the name of an epoch or era within a four age cycle. According to Hindu cosmology, life in the universe is created and destroyed once every 4.1 to 8.2 billion years, which is one full day (day and night) for Brahma. The lifetime of a Brahma himself may be between 40 billion and 311 trillion years. The cycles are said to repeat like the seasons, waxing and waning within a greater time-cycle of the creation and destruction of the universe. Like Summer, Spring, Winter and Autumn, each yuga involves stages or gradual changes which the earth and the consciousness of mankind goes through as a whole.
I give them a bit of credit in that it's the only world religion I can think of that uses such large scale numbers in their portrayals of creation stories. I mean, compared to the fundamentalists who think the universe is six-thousand years old, these guys weren't doing too shabby.
Alan Watts can explain the Yugas better than I can for anyone who's interested.
Starts at 9:07 on the first video and goes on a couple minutes into the second video.