What is stellar evolution? What evidence do we have that this happened?
What is planetary evolution? What evidence do we have that this happened?
What evidence is there that complex organic molecules are common in the universe?
How did life most likely evolve on Earth? What conditions on Earth made it possible for this to happen?
What factors determine the chances for finding life in our Galaxy?
Why would it be difficult to find life outside our galaxy?
How are we searching for extraterrestrial life?
Why are we using radio waves to search for intelligent life?
Where are the best places to look for extraterrestrial life in our solar system?