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A supernova |
Scientists have gathered a lot of evidence and information about the universe. They have used their observations to develop a theory called the Big Bang theory.
The theory states that, about 13.7 billion years ago, all the matter in the universe was concentrated into a single incredibly tiny point. This began to enlarge extremely rapidly in a hot explosion, and it is still expanding today.
Astronomers have even detected a cosmic background radiation that is thought to be the 'heat' left over from the original explosion.
The future of the Universe
Gravity is slowing down the rate of expansion - or so we believe.
The future of the Universe is difficult to predict. The evidence at the moment is finely balanced between three possibilities. The Universe might:
- expand for ever (though ever more slowly)
- eventually stop expanding, or
- eventually stop expanding, but then contract again in a “big crunch”.
There are other scientific theories for the origin of the universe. For example:
- the Oscillating Theory suggests that this universe is one of many - some that have existed in the past, and others that will exist in the future. When the universe contracts in a Big Crunch, a new universe is created in a new Big Bang.
- The Steady State Theory suggests that as the universe
expands new matter is created, so that the overall appearance of the
universe never changes.
[ This page has been adapted from www.bbc.co.uk/schools/gcsebitesize/science
]