The Origin and Fate
The Big Bang
Hubble's discovery and Friedmann's theories suggested a universal origin
at a point of infinite density, zero time, and infinite temperature. It
underwent a period of rapid inflation and rapid cooling, thus creating the
forces, matter, and time we experience today. The details of precisely how
this event occurred are not fully understood and the question of why is
one of religion and philosophy.
The Fate of the Universe
Depending on the actual value for the density of the universe, most
scientists predict three possible outcomes. All three result in different
spatial curvatures...
As has been previously discussed, a universe with enough gravity and
density of matter will close in on itself. This is a closed universe. The
picture of its evolution
over time results in a sphere-like shape with the Big Bang at one of the
poles, increases to its maximum size at the equator, and falls back in on
itself at the opposite pole.
Cosmologists suspect that a universe that has a density below the critical
value will continue to expand infinitely. The expansion rate of space will
overcome gravity. Stephen Hawking and others believe this evolution
results in a universe shaped like a saddle, or, from Professor Banchoff's
book, "the real part of the complex parabola projected from four-space
into three-space."
This model results in cold, dead, dispersed universe. The open universe
yields a not too pretty fate.
The last model results in a universe that does not collapse nor accelerate
apart indefinitely, but slowly approaches an expansion velocity of
zero.
This is represented by the middle line of this graph. The result is a
flat and infinite picture of space.
Return to cosmology main page.