Astrobiology: What Are the Characteristics of Life?

Conclusion
In searching for life in other places, there's a current interest in looking at contemporary locations on earth that are extreme, that are similar to early Earth and therefore to early Mars and possibly early Europa or early Titan. Much of the work in astrobiology actually takes place in these extreme locations, such as geothermal sites in the Antarctic or deep under the ocean. 

In conclusion, I would just like to leave you with the thought that in order to talk about life and to talk about how nanorobots are going to imitate life, we really want to have some understanding of the characteristics of life. We can learn that from the only example of life that we know and that is life here on Earth. 

Barry Blumberg is the President of the American Philosophical Society and winner of the Nobel Prize for Medicine.