[Arthur McGowan]

So if the earth had been just a little closer or farther from the sun, no people. If we had been hit by just a few more comets, no dry land, and no people. Hmmm.

[ngc6656]

So if the earth had been just a little closer or farther from the sun, no people. If we had been hit by just a few more comets, no dry land, and no people. Hmmm.

IMO, Authur, it would have required more than a few more comets. But you have hit on how critical small changes in distances (on an astronomical scale) are to the question of the existance of life as we know it in any planetary system.