How soon will Ellen need to eat her words? Probably not until long after retirement. Besides, is, say, finding bacteria on, say, Europa really an answer to the question Are we alone? I mean, if you were alone, would knowing that there were also bacteria present make you feel any less alone?

The unremarkable fact is that we have not found any evidence of even microbial life on other planets. The true question about the supposed bacterial fossils in the Mars Meteoite ALH84001 is whether is was an accidental hoax or an intentional hoax. What Ellen is saying is that the best places to look is where there is water and organic molecules. What we have found are possible preconditions for life, but that is hardly enough.