AST251H1 Midterm: AST251 Midterm Notes
21 Feb 2012
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Has drawbacks (main) time needed to detect any evolution. To search for life in the universe then, we will look for what we know: bacteria and microbes, plants, animals, intelligent life. The only life we know of right now is the life on earth - no manifestations of life currently known anywhere else. Where to look: solar system complex life seems to exist only on earth, but other planets and moons may contain microbial life, extra-solar planets in the habitable zones around stars. Three essential groups of sciences: astronomy and astrophysics. Are there other celestial bodies that may harbor life: earth sciences. How does the earth function, the only known planet with life: biology. Long time periods: myr = million yr = 1 000 000 yr = 106 yr, gyr = billion yr = 1 000 000 000 yr = 109 yr.
