ASTRON 2B03 Lecture Notes - Lecture 7: Spectroscopy, Blueshift, Imaging Spectroscopy
1 Dec 2016
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A u t h o r: yungc. jin@gmail. com midterm on oct 20th during regular class hours. Journals - talk about anything related to big questions in science once at week. Hubble"s law galaxy speed is proportional to its distance. Implications of hubble"s law from universe"s expansion: the wavelength of light being observed: the overall appearance of the universe should be changing with time. So long ago, they must have been closer to together. By looking far outward, we are looking back in time. Galaxies that are distant now were more crowded together: the universe may have had a beginning. At very beginning, the galaxies would have been crowded on top of each other. We can use hubble"s law to estimate when that first time would have been: v = hd d = v/h. 1/h = t so 1/h is a time unit. You have to make the assumption that the hubble constant doesn"t change it actually changes over time.
