Moon Seen as Haven for "Beginnings of Life"
|May 30, 2001|
Earth's moon might be a biological preserve, a celestial cemetery where protolife (the beginnings of life) or fossil extremophiles (tiny organisms that can live in extremely hostile conditions) are awaiting discovery in volcanic shadowed sites.
Permanently shadowed areas on the moon, such as the lunar north and south polesalso believed to be places that harbor quantities of water icemay contain early forms of life. If so, a go-slow approach to tapping lunar ice reserves for supporting future moon bases is a prudent step, allowing scientists to study this pre-biological bonanza.
A case for returning to the moon to look for lunar protolife was made at the National Space Society's 20th Annual International Space Development Conference held recently in Albuquerque, New Mexico.
"The possibility of protolife in shadowed areas on the moon justifies additional exploration," said Jack Green, a professor of geological sciences at California State University, Long Beach. Protolife in the form of proteinoid microspheres, as well as amino acids, could be lurking in special niches on the moon, he said.
There has been a long-standing debate about the origin of lunar surface features. That debate centers on the role of volcanism versus that of impacting meteorites or comets that have given the moon its beat up and bruised-looking face.
Green is in the camp of those who contend that the majority of major lunar features are volcanic or volcano-tectonic in origin.
In making his case, there are many Earth analogs of the volcanic variety, Green said. And he's skinned his shins trekking over some of them to back up his belief. He has studied calderas, large volcanic basins rife with gas vents, like those found in the Galápagos, as well as lava-filled spots in New Zealand, the magma fields of Toba, Sumatra, and off-center volcanoes that dot Aniakchak, Alaska.
Lunar parallels can be found in Alphonsus, Copernicus, Tycho, Wargentin, and crater Schiller on the moon, Green said.
"I believe the central mountains are volcanoes in calderas for the majority of large lunar craters," Green said. Lesser lunar gravity is likely the reason why central mountains in lunar craters are lower than crater rims, he said.
Furthermore, there have been documented bursts of probable sulfur, carbon, hydrogen, and other gases eking from the moon from time to time. These small outbursts add more evidence for lunar volcanism playing a big role in the past, Green said, and coughing up the ingredients for lunar protolife.
On neighboring Luna, early Precambrian formaldehyde, methane, ammonia, water ice, carbon dioxide, sulfur and other compounds would possibly persist as ices until the present day, Green said.
Areas on the moon that are perpetually shadowed are also super-deep freezers. Both the north and south poles on the moon offer such climes, as does the interior of the breached central mountain of Copernicus.
"Those ices would last forever, it's so cold," Green said. Prebiotic elements and compounds would not suffer ultraviolet degradation from the sun nor significant evaporation, he said.
Lunar volcanic gas plumes from these calderas carry the stuff to create amino acids, protolife forms, and conceivably, fossil extremophiles, Green said. This is especially possible in the early Precambrian when methane, ammonia and formaldehyde were more abundant.
"I'm very careful and not saying Godzilla is going to jump out of a crater. I am dealing with the most conservative protolife, the beginnings of life, that utilizes the ingredients found from gas vents," Green said.
Green said sending back to the moon more capable orbiters, outfitted with special sensors, is a must. Shadowed lunar craters would be probed from altitude, and a search undertaken to look for vents using high-resolution cameras. Subsequently, on-site geologists would study first-hand the select areas.
The philosophical implications are that volcanism implies the possibility of protolife, in so far as the ingredients for life are in the methane and the ammonia and the carbon dioxide, along with water and sulfur.
"These are the ingredients for life, and the implications are that volcanism implies protolife," Green said.
Could life be present on the moon today?
Green said he is a conservative person. "I've avoided saying life. I try to say the beginnings of life. If you have protolife and you have all this time and the advantages of a lunar shadow environment, there are so many pluses," he said.
"Everything falls into place and it's extremely favorable for life. I don't think it would be anything advanced at all. But it could be the earliest known species, the archaea, or bacteria. This is very possible. I'm not going to say they are alive, I draw the line there. But I do say it is possible because of time. They wouldn't be fried by ultraviolet radiation because they are in shadow. They would be preserved under layers of ejecta, both impact and volcanic ejecta," Green said.
Green said that, while lunar ices are a great resource for future explorers, "you have to be careful that you don't destroy those ices that might contain evidence of protolife. We shouldn't have somebody jump in and try to exploit these ices without being extraordinarily careful."
"I should like to see lunar exploration for 'life' be given a higher priority than it now has. The moon is but a long weekend away from Earth. We have been there. Can we afford not to return?"
(c) 2001 Space.com
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