Wednesday, November 12, 2008

Predisposed to Pessimism?

The overall geometry of the universe is determ...Image via WikipediaIt would seem that there is an inherent tendency towards a negative outlook within the universe.

There are basically 3 final states for the universe that depend on the space-time curvature. Each state ultimately has a rather unappealing end state.

In a closed universe the curvature is such that the universe does not have escape velocity. There will come a time when the expansion reverses and the great collapse begins. This is known as the Big Crunch. It could be that the universe will Big Bang again after the crunch but it is likely that the replacement universe will not have the same initial conditions and thus will not be the same place we know.

An open universe will continue to expand through eternity. It is likely to slow but will never reach a point where it stops expanding.

A flat universe's expansion will slow until it eventually reaches an equilibrium point. This will be a stable position. It was to attain this ideal that lead to Einstein's "greatest blunder".

Ultimately though a flat and open universe will suffer the same fate although the open universe will reach it first. When stars die, they release heavy atoms into the universal stew. Heavy atoms are not as good a nuclear fuel as the lighter elements especially hydrogen. This means that as the universe ages, the fuel available for stars does not burn as furiously as in the earlier universe. There is therefore a reduction in the energy generated.

Another consideration is that the basic elements of an atom also have a shelf-life even if it is a pretty long one.

The long term picture is not all that great. In one case everything goes splat and in the other everything eventually disperses in a haze of subatomic particles. Not a happy place.

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