AST 2002 Chapter Notes - Chapter 18: Interstellar Travel, Drake Equation, Deep Sea
Document Summary
18. 1 life on earth: learning about life on earth makes it more likely for life to be elsewhere, life can develop quickly under the right conditions on other planets. Charles darwin: evolution occurs through natural selection, where advantageous traits in a species are passed on to future generations, fossils help us see the change over time, mutations are any changes that occur in dna. 4. 3 or 4. 4 billion years ago: oxygen was most likely toxic to anything living more than 2 billion years ago. Oxygen may have played a large role in evolution: there are three basic requirements for life on earth, a source of nutrients, energy to fuel life, liquid water. 18. 2 life in the solar system: habitable worlds must contain the necessities for life, mars is a target for missions to find life. Saturn"s moons, could possibly be homes to life. Stars must allow stable orbits and have long lifetimes.
