What is the big bang?
- The big bang is a theory which says that the whole universe started expanding billions of years ago in one place with a large explosion.
- When we study the stars it can be shown that all of the galaxies are moving away from us.
- We can also observe that galaxies further away are moving quicker.
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Evidence for big bang (including red shift)
- Microwave radiation can be detected from the big bang explosion. This microwave radiation is shown as interference in badly tuned radios.
- Red shift can be used to show that the universes are moving further away.
- Red shift works, as when light sources move away, the wavelengths become longer than a closer source. This means that the wavelengths shift towards the red end of the spectrum to show the source is moving.
- The further away the more the dark line is towards the red end of the spectrum.
- The dark line shows where light is absorbed.
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