The Dust-Cloud Hypothesis
By: July • Essay • 282 Words • December 3, 2009 • 1,822 Views
Essay title: The Dust-Cloud Hypothesis
The
universe contains huge clouds made up of very
large amounts of dust and gas. About
6,000,000,000 (billion) years ago, one of these
clouds began to condense. Gravitation--the pull
that all objects in the universe have for one
another--pulled the gas and dust particles
together. As the dust cloud condensed, it began to
spin. It spun faster and faster and flattened as it
spun. It became shaped like a pancake that is
thick at the centre and thin at the edges. The
slowly spinning centre condensed to make the sun.
But the outer parts of the pancake, or disk, were
spinning too fast to condense in one piece. They
broke up into smaller swirls, or eddies, which
condensed separately to make the planets. The
forming sun and planets were made up mostly of
gas. They contained much more gas than dust. The
earth was far bigger than it is now and probably
weighed 500 times as much. The large body of
dust and gas forming the sun collapsed rapidly to a
much smaller size. The pressure that resulted from
the collapse caused the sun to become very hot
and to glow brightly.