Lecture 43: Extraterrestrial Life
What does extraterrestrial life look like? This lecture explores\ncurrent thinking about what extraterrestrial life might be like not by\nguessing their appearances, but instead applying lessons learned from\nour growing understanding of how evolution and biochemistry work on\nEarth. I will discuss Universal versus Parochial characteristics,\nConvergent Evolution, Radical Diversity, and other ideas from\nevolutionary biology that might inform how life might emerge on other\nworlds. We will then look at alternatives to carbon biochemistry,\nspecifically the possibility of silicon-based life, and alternatives to\nliquid water as a solvent medium for biochemistry, specifically the\npossible role of Ammonia. Finally I will give one example of a highly\nspeculative idea about life without chemistry. In the end, the outcome\nof such studies may not be to tell us much about extraterrestrials as to\nhelp focus questions on how we ourselves arose. Recorded live on 2009\nDec 1 in Room 1005 Smith Laboratory on the Columbus campus of The Ohio\nState University.