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| Drilling for life: Crispin Halsall, an environmental chemist, checks air and ice samples on the Beaufort Sea. Researchers
aboard a converted icebreaker, the Amundsen, have been combing the Canadian Arctic for microscopic organisms. George Tombs |
Beneath Arctic ice pack, teeming life holds extraterrestrial clues
Microscopic organisms thrive in polar-ice 'brine channels' whose conditions mirror some of those found in space.
from the April 24, 2008 edition
Page 3 of 3
The astrobiology community is hoping that a mission to Jupiter, currently being discussed by NASA, will provide more opportunities to look for life on Europa.
A number of frozen planets and moons have the potential to sustain microscopic life, scientists say. They include:
Mercury – The smallest planet of our solar system and the one closest to the sun is believed to have ice in permanently shaded craters at its poles.
The moon – Earth's satellite may have ice at its poles mixed in with regolith (a dry blanket of loose soil and rocky fragments).
Mars – Long the subject of speculation about life, this planet has water ice at both north and south poles and frost has been detected in higher elevations of the volcanic Tharsis region.
Europa, Ganymede, and Callisto – Three of Jupiter's ice-covered moons, discovered by Galileo in 1610, may have liquid-water oceans under the ice crust at the surface. If oceans exist below the ice, it may be kept warm by tidal heat.
Enceladus – This tiny moon orbiting Saturn appears to have spewing ice geysers on its surface.
"Jupiter's moon Europa is the outstanding target because of the water under its ice and the tectonically active icy crust," says Jere Lipps, an astrobiologist at the University of California, Berkeley. "Another of Jupiter's moons, Ganymede, is less likely but still a candidate, because it may also have water under its much older icy crust."
Saturn's moon Titan is another possible host, Mr. Lipps says, given the presence of many carbon compounds, "although that's not necessary, given the abundance of the elements of life in general in the solar system," he says.
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