We don't know when and where life might have existed or currently exists ...even on the planets that we know about. Some interesting things to read if you wonde

We don't know when and where life might have existed or currently exists ...even on the planets that we know about. Some interesting things to read if you wonder about such things: http://en.wikipedia.org/wiki/Sara_Seager#Seager_equation http://en.wikipedia.org/wiki/Drake_equation