The Big Bang Theory – Observational Evidence – GCSE Physics

Wherever we look in the universe, nearly all the galaxies we observe are moving away from us. We know this because the light we see from them is ‘red shifted’ – its wavelength has been stretched towards the red end of the spectrum.

This is strong evidence to support the theory that the universe is expanding and must have started from a small initial point some time in the past. This theory is called the ‘Big Bang’ theory.

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