GEOG 201 Chapter Notes - Chapter 2: Sphericity, International Space Station, September Equinox
18 Apr 2018
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Document Summary
Universe has at least 125 billion galaxy, our milky way galaxy contains 300 billion stars, our solar system is on one of the milky way"s spiral arms - the orion spur of the. Sagittarius arm: a super-massive black hole named sagittarius a* sits in the galactic center, our solar system has 8 planets, four dwarf planets. Solar system formation: the prevailing theory states that our solar system condensed from a large, slowly rotating and collapsing cloud of dust and gas, a nebula. Gravity had a big role: planetesimal hypthesis: dust cloud hypothesis, explains how suns condense from nebular clouds. In this hypothesis, small grains of cosmic dust and other solids accrete to form planetesimals that may grow to become protoplanets and eventually planets. Initial results from the orbiting kepler telescope estimate the number of planets in the. Milky way at 50 billion, with some 500 million planets in habitable zones. (moderate temperatures and liquid water.
