Earth-SolarSystem - the greatest mysteries in astronomy o...

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How is Earth moving in our solar system? Contrary to our perception, we are not sitting still We are moving with the earth in several ways, and at surprising fast speeds Earth rotates around axis once a day Earth orbits the Sun (revolves) once every year: o At an average distance of 1 AU roughly 150 million km o With Earth’s axis tilted by 23.5 degrees (pointing to Polaris) o And rotating in the same direction it orbits, counter- clockwise as viewed from above the north pole Our sun moves relative to the other stars in the local Solar neighborhood o Typical relative speeds of more than 70,000 km/hr o But stars are so far away that we cannot easily notice their motion o Orbits the galaxy every 230 million years Earth 5 billion years old More detailed study of the Milky Way’s rotation reveals one of
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Unformatted text preview: the greatest mysteries in astronomy: o Most of Milky Way’s light comes from disk and bulge o But most of the mass is hidden in its halo • How do galaxies move within the universe? o Galaxies are carried along with the expansion of the universe o Those further away from us seem to be expanding faster than those closer to us (raisen bread) o Expanding universe figured out by Edwin Hubble All galaxies outside our local group are moving away from us The more distant the galaxy, the fast it is racing away We live in an expanding universe • Never still o Earth rotates on axis 1000 km/hr o Earth orbits Sun: 100,000 km/hr o Solar system moves among stars: 70,000 km/hr Milky Way rotates...
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This note was uploaded on 03/16/2011 for the course ASTR 002 taught by Professor Corcoran during the Spring '11 term at GWU.

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