lecture11 - The History of Earth and Life Lecture 11 1...

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Unformatted text preview: The History of Earth and Life Lecture 11 1 Lecture 11 - The Formation of the Solar System Star Formation, Supernovae, Star Cycles Star Formation Gas clouds (a gas cloud = nebula ) are the place where stars (and planets) form Composition of a star (and its planets) reflects the composition of a nebula from which they formed Supernovae Supernovae are incredibly energetic Material ejected from a supernova is the only known source heavy elements If this material becomes part of a gas cloud that forms a new star the heavy elements made in that supernova will become part of that new star Star Cycles Only few lightest elements were present when the universe first began to expand From clouds of light elements first giant stars formed Eruptions of giants (supernovae) produced heavy elements Materials ejected into space by supernovae become part of newer stars Star formation, fusion reactions, and supernovae explosions are a cyclic process Solar System Solar system formed about 4.5 to 5 billion years ago Over 5 billion years after the origin of the universe and the development of the Milky Way How do we know? 1. Presence of heavy elements in the solar system The solar system contains heavy elements that could only have accumulated over time from older stars. Therefore, Solar System must have formed long after our galaxy formed 2. Radioactive dating of meteorites Dating of meteorites (primitive material of the solar system) indicates that solar system formed about 4.5 to 5 billion years ago 3. Explosion of Supernovae Daughter products of very fast decaying isotopes only produced in supernova explosions...
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This note was uploaded on 03/24/2008 for the course GEOS 1014 taught by Professor Sxiao during the Spring '08 term at Virginia Tech.

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lecture11 - The History of Earth and Life Lecture 11 1...

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