PHIL 008 Lecture Notes - Lecture 29: Cosmic Microwave Background, Edwin Hubble, Moe Williams
29 Oct 2020
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Document Summary
How the universe began - big bang theory. Proponents of standard big bang" theory generally accept the following three main lines of evidence: If we look at an object through a spectroscope that is moving away from us, the wavelength of the object shifts towards the red end of the spectrum. On the other hand, if we look at an object that is moving towards us, the wavelength of the object shifts towards the blue end. This is the doppler effect, the basis, for example, of radar guns" used by the police to measure the speed of cars. In the 1920"s edwin hubble observed that the colours emitted by distant galaxies are shifted consistently toward the red end of the spectrum. This supports the hypothesis that the universe is expanding. Hubble"s law (which was first derived by abb lema tre) states that the observed velocities of galaxies are proportional to distances from the galaxies to us.
