CAS AS 101 Lecture Notes - Lecture 4: Northern Hemisphere, Celestial Equator, Depth Perception
30 Jan 2018
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Document Summary
More detailed study of the milky way"s rotation reveals one of the greatest mysteries in astronomy. Mass is mostly in the center, thus the stars in the center should rotate much faster than the stars in the outer side. However, the stars on the outer edge moves at a speed similar to the stars in the center. There is something on the outer edge that we can"t see that enables such phenomena. Dark matter is responsible for clumping the galaxy together. Galaxies are carried along with the expansion of the universe. All galaxies outside our local group are moving away from us. The more distant the galaxy, the faster they move away. = our universe is expanding as a whole. Farther away, the galaxies are moving away much faster because of its distance. We are also moving on the same speed. When the speed is constant, you don"t feel the movement.
