GEOL 101 pg12-29 outline

GEOL 101 pg12-29 outline - January 18- Cosmology and the...

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January 18- Cosmology and the Birth of Earth pg.12-29 Cosmology: the study of the overall structure and evolution of the universe Structure of the Universe Geocentric model: Earth sits motionless at the center of the Universe while the Sun and all planets follow perfectly circular orbits around it. Heliocentric model: all planets, including Earth, orbit the Sun. This theory did not gain popularity till the Renaissance. The distance from Earth to Celestial Objects A light year, the distance that light travels in one Earth year, equals about 9.5 trillion km Galaxy: immense systems or groups of stars. The Universe consists of over 300 billion galaxies. Our solar system lies near the outer edge of the Milky Way Galaxy. How can we determine if a Star is moving? The Doppler Effect. Waves are disturbances that transmit energy from one point to another by causing periodic motions. As each wave passes, air alternately compresses, then expands. The pitch of the sound depends on the frequency of the sound wave, meaning the number of waves that pass a point in a given time interval. When the train moves toward you, the sound has a high frequency (the waves are closer together), because the sound has moved slightly closer to you between the instant that it emits one wave and the instant that it emits the next. When the train moves away from you, the sound has a lower frequency (the waves are farther apart), because the sound has moved slightly farther from you between the instant it emits one wave and the instant it emits the next. The color of light you see depends on the frequency of the light waves. The red light has a longer wavelength (lower frequency) than blue light (higher frequency). If the light source moves away from you, the light you see becomes redder (as the light shift to lower frequency). If the light source moves towards you, the light you see becomes bluer (as the light shifts to higher frequency). Hubble discovered that the light from all distant galaxies, regardless of their direction from Earth, exhibits a red shirt. AKA Expanding Universe Theory AKA bread dough with raisins. Big Bang Theory – all matter and energy (everything that now constitutes
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GEOL 101 pg12-29 outline - January 18- Cosmology and the...

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