What is Life?

So what are the universal features of life, apart from how we define it down here on earth?

Ken Nealson
Director, Center for Life Detection
Jet Propulsion Laboratory, NASA/Caltech

...what might be the fundamental features of life?

Life uses energy. What are the sources of energy on a planet? Can we look at the ways that energy moves around?

Uh, life makes products some of which are gases, some of which are liquids, some of which are solids.

Uh, if we found those products when they shouldn't be there, Sherlock Holmes-as we all have to be-would start to claim there must've been life here, or maybe its still there.