Red-Shift

• there is an observed increase in wavelength of light from most distant galaxies
• the further away the galaxies...

  the faster they are moving and the bigger the observed increases in wavelength (red-shift)
• the observed red-shift provides evidence that space itself is expanding and supports the Big Bang theory
• what does the big bang theory suggest

  the universe began from a very small region that was extremely hot and dense
• from 1988 onwards, observations of supernovae suggest that distant galaxies are receding ever faster