Hi Joe I'm sure the scientists do have such conversations among themselves, but given how badly almost any scientific news is covered in the media (present company excepted), I'm sure they know a minor comment like that would be tomorrow's headline. Who needs that? I think any good scientist who was looking at these little blobs and thinking life, would be trying to understand the chemistry, looking for energy sources and metabolytes and then comparing those results against other likely scenarios. I'm perfectly comfortable with their taking plenty of time on this. Although it's certainly good to look for analogs in geological processes on earth, there are still going to be big differences. So far, we don't have evidence that Mars ever had the kind of tectonic activity that plunges materials miles into the earth and cooks them up into all sorts of stuff. We don't know if the gravity difference affects the possible sizes of crystals or concretions formed by precipitation from a solution. I'm sure a real geologist could raise many other issues. Carl Sagan still said it best: "Extraordinary claims require extraordinary evidence". Best regards, Michael You're absolutely right that they should be cautious. But it's NOT cautious to automatically rule out possibilities without investigating them. And NASA has not mentioned it's even mulling any thoughts that these things might involve life.