EAS 1540 Lecture Notes - Lecture 1: Galaxy Formation And Evolution, Big Bang, Atomic Number
5 Aug 2016
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Summary of universe/galaxy/star formation: the big bang happened 15 billion years ago: all mass contained in a single point explodes outwards, mass cools and collapses gravitationally. 3. temps in the core of large masses increase due to compressional heating. 3. 1. 1. when core temps reach 10 million degrees k, nuclear fusion of h into he is ignited (thermonuclear fusion reaction) to form heat and visible light (among other types of radiation) Elements heavier than iron are only formed when the star explodes: every single carbon, nitrogen, and phosphorous atom making up your physical body today was, at one point, sitting in the center of a boiling hot star!! You are very truly made of star dust! Inner planets made of rock and material. Summary of solar system/earth formation: 4. 6 billion years ago, rock forming elements condensed into small solid grains as the nebula cooled, grains accreted to planetesimals, such as asteroids and comets, planetesimals accreted to form earth.
