I see four possibilities for how life got started on earth, listed in descending probability. 1. Genesis of life occurred on earth. 2. Genesis of life on another planet (probably outside of the solar system). Followed by transport of DNA to earth by natural means. This possibility becomes more likely if it turns out that the genesis of life is rare. 3. Accidental seeding of life on earth by an extraterrestrial probe. 4. Purposeful seeding of life on earth. I consider this possibility to be extremely remote if for no other reason than it was a royally botched job. (unless it doesn't matter to the seeder that the process would take 4 billion years). ********** Before the advent of telescopes that will allow us to detect extraterrestrial life, does anybody care to make any predictions about what we will find about the distribution of life in the galaxy, given each of the 4 cases? I am not asking just about spacial distribution, but also distribution varying by type of planet (or even type of star). ********** Yes, we have no data (other than negative SETI results), so this is not science. More of a logic puzzle where you will have to wait 4 or 5 decades to find out if you are right.