We Are All Aliens!

I love this article in which Professor Chandra Wickramasinghe says that life was brought here to Earth by comets, a theory he jointly proposed called panspermia in which interstellar dust is partly organic in nature and in comets.
This reminded me of an excellent episode of Star Trek: The Next Generation entitled "The Chase," where Captain Picard is contacted by his archeology professor who is collecting DNA samples. When the professor is killed, Picard is left to piece the puzzle together of the DNA samples and in the end discovers that Humans, Romulans, Klingons, and Cardassians all share some common DNA that was seeded throughout the galaxy by an elder race. It is a fascinating episode and in some way relates to the theory of panspermia the difference being an ancient race spread the seeds of life, so to speak.