NATS 1880 Study Guide - Geocentric Model, Planetary Science, Astrobiology
23 Nov 2012
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Observations : 1) hypothesis = limited validity 2) model = hypotheses verified in limited circumstances 3) theory or law = hypotheses confirmed by multiple experiments. Habitable planets = planets that have the right conditions for life, does not necessarily mean they have life. Laws of physics are universal throughout the universe. Building blocks of life (organic molecules) have been found elsewhere in the universe. Liquid (water?) seems essential, a source of heat or energy, enough. Extremophiles = life that can withstand a variety of extreme conditions (frigid temperatures, etc) time to develop long chain complex organic molecules, protection from radiation. Mars, and the moons of jupiter (europa) and saturn are likely candidates where life may be found. Our galaxy contains approximately ~200 billion stars and is 100000 light years across. Light year = distance light travels in 1 year. Seti uses radio telescope searches to look for signs of intelligent life, and has been ongoing since.
