ASTRON 2B03 Lecture 8: Astron 2BO3 Lecture 8 Expansion
18 Mar 2016
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Speed = constant x distance v = hd. So it looks like the number (1/h) is a time (1/h) is a time. It is the time since the expansion began. Measuring galaxies in many diff directions we nd just the same proportionalility b/w distances. Galaxies are moving through the expansion of the universe, as well as their own systemic velocity. Groups of galaxies get farther apart form each other over time, any one group or cluster holds itself together by its own total gravity. They are gravitationally bound, so the expansion of our universe doesn"t affect us, anything in a local group is still bound together by gravity. The milky way sees a blueshift from andromeda, all galaxies are redshifted outside of our local volume. Timeline: we have strong evidence that the universe actually bega about 13. 7 bill years ago, if you put it in terms of a year . 12:00:01 matter, energy, light all have taken their present forms.
