He is currently the senior scientist for astrobiology at the NASA Ames Research Center in Mountain View, California.
[6] He has an extensive research record in observational cosmology but more recently works on topics in exoplanetary science and astrobiology.
[1] He is the author of the upper-level undergraduate textbook Extrasolar Planets and Astrobiology,[7] published in 2008 by University Science Books, CA.
His blog Life, Unbounded appears at Scientific American and covers topics in astronomy, exoplanetary science, and astrobiology.
[11] It was listed as one of the New Scientist top 10 books to read in 2012 and as one of The Barnes and Noble Review Editors' Picks: Best Nonfiction of 2012.