What are three major observations that support the Big Bang Theory?

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Mar 20, 2016


The three major observations that support the Big Bang Theory are: 1. Hubble expansion, 2. Cosmic microwave background (CMB), and 3. Primordial abundances of light elements.


  1. The redshift of distant galaxies indicates that galaxies appear to be moving away from us at speeds proportional to their distance. This is called "Hubble's Law." This observation means that the universe is expanding and suggests that the entire universe must have been located in a single point billions of years ago as predicted by the Big Bang Theory.

  2. The CMB is characteristic of black body radiation at 2.7 K, which pervades the entire universe and is viewed as a relic of the high energy, early universe. The Big Bang Theory not only predicts that this glow should exist, but that it should be moving so fast away from us that the wavelength of this radiation would have been shifted from visible light to the microwave radiation we see today.

  3. As the universe expanded and cooled, some of the "light elements" (hydrogen and helium) were created. The Big Bang Theory predicts how much of each element should have been made in the early universe, and accounts nicely for the current observed abundances of most elements in space.

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