Methane On Mars (broadcast Friday, January 16th, 2009)

This artist's concept depicts NASA's Phoenix Mars Lander a moment before its planned touchdown on the arctic plains of Mars in May 2008. NASA /JPL-Calech / University of Arizona

This week astronomers reported finding an unexpected gas -- methane -- in the Martian atmosphere. On Earth, a major source of methane is biological activity. However, planetary scientists aren't ready to say that life on Mars is to blame for the presence of the gas there, as geochemical processes could also account for the finding. The find is intriguing especially because the researchers say they have detected seasonal variations of methane emissions over specific locations on the planet. We'll talk with one of the researchers on the project, reported this week in the journal Science, about how they found it, and what that might mean for life on the Red Planet.