ASTRON 2B03 Lecture Notes - Lecture 22: Kuiper Belt, Oort Cloud, Homo Sapiens
2 Dec 2016
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Document Summary
2. 5 millino years ago - first homo sapiens. 4. 5 billlion - formation of earth e. g revised drake equation asks for biosignatures of life -> gives much broad definition. Terrestrial planets form close in, gas giants further out: when sun turn"s on (goes nuclear), all the dust b/w planets are cleared out anything heavier than iron must ne enriched by a supernova (will discuss later) Small solar system objects (made same time as anything else in solar system, including. Comets form in outer portion of disk about the sun. Gravity from big planets threw most of these out of the solar system so comets formed in same place as planets were kicked out. Kbos and oort cloud are remnants of nebula where solar system was formed (artifacts of early solar system) Oort cloud is a sphere not a disk since gravity caused all comets to fly into random directions. There are also short-period comets (hailey"s comet) in asteroid.
