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Life might exist on one of Jupiter's moons


Arizona Daily Wildcat

Image courtesy of NASA/JPL University of Arizona researcher Richard Greenberg theorizes that one of Jupiter's moons, Europa, could be home to extraterrestrial life. An image created by NASA scientists illustrates this theory.

By Blake Smith
Arizona Daily Wildcat,
March 28, 2000
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If a UA professor's predictions prove true, one of Jupiter's moons - Europa - could be home to the first-ever confirmed extraterrestrial life.

And scientists will help confirm his prediction by studying a lake here on planet Earth.

Researchers are planning an exploration of Antarctica's Lake Vostok - a lake that was frozen more than 30 million years ago and now sits below two and a half miles of solid ice - which could be key in determining the existence of life on Europa.

If life is found in the lake, it could boost scientists' claims that life exists on the moon, because of similar physical arrangements between the lake and Europa, according to University of Arizona planetary sciences professor Richard Greenberg.

He said before Lake Vostok froze over, it housed the same sea creatures that are found in the oceans today.

"Basically, we are looking for the survivors of 30 millions years ago," said Greenberg.

Because the ice on the lake is thick, and light has not reached the lake for millions of years, Greenberg said he is not sure what would be found in the body of water.

Lunar and Planetary Laboratory researcher Paul Geissler said the probability of finding advanced life in the lake is minimal.

"Some models suggest that any life present would be limited by energy constraints to primitive forms such as bacteria, while others paint a more optimistic picture. However, it would be extremely profound to find even an amoeba," Geissler said in an e-mail interview.

Finding creatures under the lake, however, does not guarantee life will be found on Europa, Greenberg said.

He said the physical characteristics of Europa - including whether there is an ocean on the satellite - are not fully understood, and Europa needs to be explored further.

"Some people say that the ice on Europa is so thick that there are no cracks," he said.

Greenberg said he thinks the surface is a clustering of thin ice that moves in a tidal motion - where the ice expands and contracts - allowing water to reach the surface.

If the surface of Europa behaves as Greenberg suggests, there is a slight possibility that photosynthesis could take place on surface.

"Photosynthesis would be hampered by Europa's greater distance from the sun. It receives only one-twenty-fifth as much sunshine, and this energy has to penetrate through a few meters of ice even if water nearly reaches the surface in flooded cracks," Geissler said.

Greenberg said the possibility of photosynthesis still exists.

More extensive pictures of the surface of Jupiter's moon could be taken in the next eight to 10 years. A lander could be on the way to Europa within 15 years as well, Greenberg said.

"If we find direct evidence of an ocean, then the orbiter will almost certainly be followed up by other investigation including landers and perhaps even drill rigs to explore the subsurface," Geissler said.

To clear up some of the lingering questions about the composition of the surface of Europa and what might be under it, scientists could use the same technology that is being used on Lake Vostok.

For instance, scientists discovered Lake Vostok using an ice-penetrating radar.

"The discovery of Vostok by ice-penetrating radar is similar to the strategy planned for the next Europa mission to look for places where the ice might be thin and the ocean within reach of further exploration," Geissler said.

"And the technology being developed to explore Lake Vostok, including thermal drills, miniature instruments for biochemical analysis, and submersible vehicles, might one day be used to probe beneath the surface of Europa," he added.

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