Lect_1_Intro

Evolution of the solar system evolution of the solar

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Unformatted text preview: r System Evolution of the Solar System Evolution of the Solar System Evolution of the Solar System Evolution of the Solar System Our Solar System The whole solar system is about 4.6 billion years old. In the first step of the formation of our solar system, a gaseous cloud begins to collapse due to gravity. In the second step, a star forms and burns off its gases, and lastly the planets form. How do we know this? We can see it happening in other parts of the universe. Below are two pictures of nebula in the star formation stage taken by the Chandra X-Ray observatory satellite. We can also see stars die...this picture (also from Chandra) shows the remnants of a supernova explosion at the end of a star's life. We can observe the speed and direction at which galaxies are moving away from (and they're pretty much all moving away since the universe is expanding). We can then figure out that in the very distant past, all the galaxies were at the same place at the same time - The Big Bang, the birth of the universe, ~15 billion years ago. How do we know how fast galaxies are moving away from us? We can measure galactic velocities by measuring the redshift of their light, which is how much the light has shifted towards the red end of the light spectrum (similar to the Doppler shift that affects sound waves emanating from a moving source). Another way we can learn about the Big Bang and the birth of the universe: by measuring the Cosmic Microwave Background. The first observation of the cosmic microwave background was accidental......
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This note was uploaded on 09/05/2009 for the course GEOL 240Lxg taught by Professor 12:30-01:50pm during the Fall '07 term at USC.

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