NATS 1880 Lecture Notes - Lecture 7: Solar System, Solar Wind, Chemical Polarity
25 Jun 2017
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Requirements for life molecules (likely), energy (less likely), liquid water (unlikely) Chemical elements: 25/90 used on earth (96% of life = oxy, carb, hydro, nitro) Solar nebula: condensation/accretion only works on heavier elements (c/n/o), so we expect extrasolar planets to contain these elements anyways. Organic molecules: amino acids from deep-sea vents, space, impact heat/pressure, Interplanetary dust: organic molecules spread throughout space but destroyed by solar wind or beneath the surface where no reactions/movement occurs without water or gas. Amino acids: 50 in nature, 20 life on earth, amino refers to the nh2 group in the molecule & acid refers to the cooh (carboxyl) group. Photosynthetic life must have larger surface area, more ef cient, or slower metabolism to live with weaker sun. Chemical energy: created by chemical reactions of molecules. Reactions only occur if molecules are mixed together - need atmospheric gases or liquid water for this. Liquid water: chemical reactions, transport in/out cell, & metabolic reactions.
