ASTR 1000 Lecture Notes - Lecture 27: Cambrian Explosion, Planetary Migration, Stromatolite
29 Nov 2016
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Astr1000 lecture 27: life in the solar system. Rocks from space can be a big problem on earth. 2013 chelyabinsk event in russia was like 30 hiroshima bombs. We have 2 major ways to detect exoplanets: transits (eclipses), and doppler velocity shifts of the host star. Planets are incredibly common there is at least one around every star. And our solar system has some special features (location of giant planets) than not all systems share. But we"ve detected lots of massive planets close to their star. Time and new telescopes should allow detection of more planets with earth"s size and distance. We still have to explain the existence of hot jupiters (really big planets, really close to the star) Life quite possibly started several times, but could not survive the sterilizing impacts. Carbon isotope signatures unique to life found in rocks. Implies life got started very quickly after the end of the heavy bombardment period.
