Overview Astrobiology

Although astrobiology is an emerging field, and still a developing subject, the question of whether life exists elsewhere in the universe is a verifiable hypothesis and thus a valid line of scientific inquiry. Astrobiology is a multidisciplinary field utilizing physics, biology, and geology as well as philosophy to speculate about the nature of life on other worlds. One commentator on the field, planetary scientist David Grinspoon, calls astrobiology a field of natural philosophy, grounding speculation on the unknown in known scientific theory (Grinspoon 2003). Since we have only one example of a planet with life (the Earth), most of the work is speculative and based on current understanding of physics, biochemistry, and biology.[11][12]

Though once considered outside the mainstream of scientific inquiry, astrobiology has become a formalized field of study. NASA now hosts an Astrobiology Institute.[13] Additionally, a growing number of universities in the United States (e.g., University of Arizona, Penn State University, and University of Washington) Canada, Britain, and Ireland now offer graduate degree programs in astrobiology.

A particular focus of current astrobiology research is the search for life on Mars.[14] There is a growing body of evidence to suggest that Mars has previously had a considerable amount of water on its surface; water is considered to be an essential precursor to the development of life, although this has not been conclusively proven.[15] At the present, the creation of theory to inform and support the exploratory search for life may be considered astrobiology's most concrete practical application.

Missions specifically designed to search for life include the Viking program and Beagle 2 probes, both directed to Mars. The Viking results were inconclusive and Beagle 2 failed to transmit from the surface and is assumed to have crashed. A future mission with a strong astrobiology role would have been the Jupiter Icy Moons Orbiter, designed to study the frozen moons of Jupiter—some of which may have liquid water—had it not been canceled. In 2009, NASA plans to launch the Mars Science Laboratory Rover which will continue the search for past or present life on Mars using a suite of scientific instruments.