The truth is out there, and it may be closer than you think.
Recent data from the Mars rovers and the Huygens probe on Saturn's moon Titan reveal tantalizing evidence that life existed or still exists elsewhere in our solar system.
Addressing a crowd of about 45 at the UW Space Place yesterday, astronomer David Grinspoon discussed the robots' latest photographs, focusing on their implications for the existence of extraterrestrial life.
Grinspoon is a planetary scientist with the Southwest Research Institute in Boulder, Colo.
NASA landed its two Mars rovers in January 2004, hoping they would find evidence of water. The rover Spirit landed in what appeared to be a dry lakebed, but every rock it examined was basalt-a volcanic rock.
\In one sense it was disappointing because we wanted to find evidence of water, which this didn't provide,"" Grinspoon said. ""On the other hand, this was exploration-something new.""
After a yearlong two-mile journey, Spirit discovered different volcanic rocks that appear to have once been infused with water and salts.
The crater that rover Opportunity examined revealed evidence of many wet and dry periods on Mars. One rock it found was 40 percent sulfate salt, like rocks found in Utah's salt flats.
""I could be wrong, but I believe we proved these rocks formed in watery conditions,"" Grinspoon said.
Whereas Mars gives us a glimpse of past life, Saturn's Titan may hold clues to something more current.
""Titan has a methane atmosphere, one-and-a-half times thicker than Earth's,"" Grinspoon said. That means it has wind and most likely a climate cycle like Earth's water cycle except with liquid methane. On Earth, methane is generally associated with organic life.
Most interesting about Titan, Grinspoon said, is it has almost no craters, like Earth. This suggests dynamic processes on the surface-perhaps liquid flow, wind or erosion-that fill craters back in. Photographs seem to reveal both solid ground and bodies of liquid. Because Titan has an atmosphere, scientists may be able to use helicopters or dirigibles as probes rather than ground-based rovers.
UW-Madison graduate student Peter Susalla was particularly intrigued by the Titan photographs.
""Titan is such a dynamic world,"" he said. ""It's cool to have a peek into such an exciting place.""
Space Place director Jim Lattis said these observations are vital for humanity.
""It's as important for humans to explore the world as it is for them to write poetry or compose a symphony,"" he said. ""Research like this helps us develop a personal connection to the universe.""
