* Chair, Department of Astrophysics
* University of Chicago
* Director, Cardiff Center for Astrobiology
* Cardiff University
* Chief Executive Officer
* Professor of Planetary Science
* University of Arizona
Bacteria live in some of the harshest environments known, from Antarctic ice to deep sea vents. Now some researchers believe they may exist on Mars, and perhaps even outside our solar system. Is there life beyond Earth? In this hour of Science Friday we'll discuss the possibility of extraterrestrial microbes. Plus, a look at the dark days of the universe — before there were stars.