ASTR 101 Lecture 44: ASTR 101 - Lect 44
26 Dec 2017
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Have observed amino acids in nebula, on other planets, etc. Gases with uv light can eventually form aa. But no one"s gotten from here to producing an organism. Number of civilizations in our galaxy that we might be able to communicate with. R = avg rate of star formation per year in our galaxy. To estimate, take total number stars seen in the galaxy and divide per years that galaxy has existed. About 10% of the stars we"ve observed have planets but likely there should be more (even up to 100%). Anywhere between 1/8 and 3/8 within the habitable range. Habitable range has to look at entirety of galaxy. Stars in grey zone have too few metals to form earth-like planets. If occurred randomly, catastrophic event needed to occur - equation close to zero. But if you look at number of aa in the galaxy, factor is 100%. Opinion decides whether or not there is 0-100% factor.
