News Service Louisiana State University Office of Public Relations Baton Rouge, LA 70803 Phone: 504-388-8654 Fax: 504-388-3860 Contact Ronald Brown, LSU News Service Date: 09/26/97, 02:24 PM
Stone, who spoke Thursday night at the Lod Cook Alumni Center as the Max Goodrich Distinguished Speaker, chronicled NASA's search for life on other planets, beginning with the 1976 landings of the Viking spacecraft on Mars. Although those experiments turned up nothing, the discovery on earth of tube worms living in the near-boiling waters of deep ocean vents, and algae living beneath the ice sheets at the polar caps proved that life is much more robust than originally thought, he said.
Indications of life from a Martian meteorite found at the South Pole also gave impetus to the search for life elsewhere.
Stone said it is unlikely that life will be found on the surface of Mars because the sun's ultra-violet rays tend to sterilize the surface, but if there is liquid water underground, some form of life will probably be there. Part of the mission of the Mars surveyor, which arrived at Mars last week, will be to look for "hot spots," where there may be liquid water. It will be these hot spots where further exploration for life will take place, he said.
NASA has plans to send spacecraft to Jupiter's moon, Europa, and to Saturn's moon, Titan, to look for liquid water. Both spacecraft should arrive in 2004.
The surface of Europa is thought to be ice, with the possibility of liquid water beneath. Eventually a spacecraft may be sent to drill through the ice to gather information about Europa's climatological history and to probe the liquid water beneath.
Titan, as large as the planet Mercury, has a methane atmosphere, Stone said, but such an atmosphere is excellent for the formation of large, complex organic molecules -- the type which gave rise to life on earth. The Cassini spacecraft, which is now in Florida, will explore the chemistry of Titan's atmosphere and map its surface.
Another promising area in the search for life is on the surface of a comet. Comets are covered with a black, sooty residue which may be organic, he said. What this residue is, where it came from and whether it might possibly have seeded life on earth are all questions that need to be explored. Plans are under way to capture some of this residue during a comet fly-by in 2004 and return it to earth.
Although Jupiter has atmospheric zones that are temperate and should contain liquid water, Stone said he did not expect life to be found there because the gasses in the atmosphere are constantly rising and falling out of these zones. There are no stable places for life to get a foothold, he said.
And because NASA has made the search for life a high priority, exploration of Venus must wait until later. Venus has a surface temperature of 900 degrees and little or no water, so it is an unlikely place to search for life.
Other projects include connecting the two Keck telescopes in Hawaii in such a way that they will act as part of a mirror with a diameter of the distance between them, and plans for an orbiting telescope based on the same principles. This might permit us to see earth-sized planets around other stars. An earth-sized planet is one-billionth as bright as its star, Stone said.
Ultimately, humans will be sent on a three-year, round trip to Mars. The challenges in feeding them, protecting them and getting them back are being addressed by NASA now.
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