red-shift

• there is an observed increase in the wavelength of light from the most distant galaxies, and the further away the galaxies, the faster they are moving and the bigger the observed increase in wavelength. This is red-shift
• since 1988, scientists have observed light from supernovae that suggests that distance galaxies are receding even faster
• red shift provides evidence for the Big Bang Theory as the observations of red-shifted light when observing distant galaxies shows that the universe itself is expanding. Cosmic Microwave Background Radiation is also further evidence for the Big Bang Theory
• The Big Bang Theory is a theory that suggests the universe was once a very small, extremely hot and dense region, and a giant explosion then occurred which caused the universe to expand
• there are still many things about the universe that scientists still don't understand including dark mass and dark energy
• red-shift is when light from distant galaxies show an absorption spectra pattern that has been shifted to the red side of the spectra
• red-shift occurs because the light emitted by an object moving away from us will be stretched. The stretching causes the light's wavelength to increase. The faster an object moves away from us, the larger the red shift.
• why we believe the big bang theory:

  • light that reaches earth from other galaxies shows red-shift, and the further away the galaxy the more red-shifted its light is
  • this suggests that all galaxies are moving away from us and away from each other, supporting the big bang theory which suggests the universe itself is expanding
  • if we extrapolate further and further back in time, it implies that the universe must have been smaller in the past
  • so ultimately, it is believed that the universe started from an extremely hot, dense sphere of mass which had all the mass and energy in the universe