The Origin of the Earth
The Early History of the Universe
The history of the Universe may be described in the following stages:
- At the beginning of the Universe (ca. 13 billion years ago) all matter
was in one place at a single instant. This event in cosmological parlance
is known as a 'singularity', a term which describes the inference that an
infinitely large amount of matter is gathered at a single point in space-time.
- At the Big Bang there was a huge expansion of matter, an expansion which
has continued ever since.
- However, between 10-50 and 10-30
sec after the big bang there was a particularly rapid expansion of the Universe.
This process is known as inflation. Later expansion slowed to a more normal
- During inflation the part of the Universe that we see today expanded by
a factor of 1060. At this point the universe
was permeated with radiation and subatomic particles (plasma/dark matter).
- After 100 000 yrs conditions in the Universe were similar to those today
inside the sun. An almost uniform plasma of electrons and hydrogen and helium
ions filled the Universe. At this time the free electrons acted as a block
to photons — generated from the light energy generated in the Big
Bang, and prevented them escaping and rendering the early Universe opaque.
- Aafter 300 000 yrs temperature dropped to 4500°K gave rise to atomic
matter (hydrogen helium and deuterium) and because the electrons were now
removed (in the atoms), radiation streamed out and the Universe became transparent.
- As the universe continues to expand the radiation will appear to be derived
from a much cooler body, so that today the Cosmic Background radiation is
3.73 deg above absolute zero.