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Alien life in our Solar System? Study hints at Saturn's moon

เผยแพร่:   โดย: MGR Online

(FILES) In this file photo taken on October 31, 2005 The moon Enceladus seems to hover above the outer reaches of Saturns B ring in this NASA image released 31 October, 2005. Below and to the right of Enceladus, four faint bands lie in the center of the dark Cassini Division. Recently, scientists have speculated that the particles that make up the dense B and A rings might be more like fluffy snowballs than hard ice cubes. The conclusion is based on temperature data obtained by the Cassini spacecraft. Enceladus diameter is 505 kilometers (314 miles). The icy moon is on the near side of the rings in this view. This image was taken at a distance of approximately 2.3 million kilometers (1.4 million miles) from Enceladus. The image scale is 14 kilometers (9 miles) per pixel on Enceladus. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. AFP PHOTO/Ho/NASA

February 28, 2018
(AFP) - Humanity may need look no further than our own Solar System in the search for alien life, researchers probing one of Saturn's moons said Tuesday.

The icy orb known as Enceladus may boast ideal living conditions for single-celled microorganisms known as archaeans found in some of the most extreme environments on Earth, they reported in the science journal Nature Communications.

A methanogenic (methane-producing) archaean called Methanothermococcus okinawensis thrived in laboratory conditions mimicking those thought to exist on Saturn's satellite, the team said.

On Earth, this type of archaean is found at very hot temperatures near deep-sea hydrothermal vents, and converts carbon dioxide and hydrogen gas into methane.

Traces of methane were previously detected in vapour emanating from cracks in Enceladus' surface.

"We conclude that some of the CH4 (methane) detected in the plume of Enceladus might, in principle, be produced by methanogens," the researchers in Germany and Austria wrote.

They also calculated that sufficient hydrogen to support such microbes could be produced by geochemical processes in Enceladus' rocky core.

The authors had set out to test the hypothesis that conditions on the satellite may be good for hosting methanogenic archaea.

The data, based purely on laboratory study, showed this "could be" so, said Simon Rittmann of the University of Vienna who co-authored the scientific paper.

But the results provide "no evidence for possible extraterrestrial life," he underlined to AFP.

"Our study only concerns microorganisms. I would like to avoid any speculation about intelligent life," he said.

Saturn is the sixth planet from the Sun, separated from Earth only by Mars and Jupiter.

It has dozens of moons.

Previous research suggested that Enceladus sports an ocean of liquid water -- a key ingredient for life -- beneath its icy surface.

The moon is also thought to contain compounds such as methane, carbon dioxide, and ammonia, and its south pole sports hydrothermal activity -- a combination of traits that makes it a key target in the search for extra-terrestrial life.

Further research is needed to exclude the possibility that Enceladus' methane may come from non-biological, geochemical processes, the authors said.


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