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  • Oct 21, 2014
  • Updated: 1:14pm
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SPACE

Scientists say ancient lake on Mars could have been hospitable for life

Scientists say that the idea of the planet sustaining living things is plausible

PUBLISHED : Tuesday, 10 December, 2013, 9:36pm
UPDATED : Wednesday, 11 December, 2013, 3:29am
 

About 3.5 billion years ago, just as life is thought to have first arisen on earth, Mars also had a large freshwater lake that might well have been hospitable to life, scientists report.

The lake lay in the same crater where Nasa's Mars rover Curiosity landed last year and has been exploring since. The water body lasted for hundreds or thousands of years, and possibly much longer.

Whether any life appeared on Mars is not known, and Curiosity was not designed to answer that question. But the data coming back from the planet indicates that the planet sustaining life, at least in the ancient past, is at least plausible.

John Grotzinger, a professor of geology at the California Institute of Technology who is the project scientist for the Curiosity mission, said that if certain microbes such as those on present-day earth had plopped into that ancient Martian lake, they would most likely have found a pleasant place to call home.

"The environment would have existed long enough that they could have been sustained, prospered, grown, multiplied," he said. "All the essential ingredients for life were present.

"Potentially the aqueous stream, lake, groundwater system could have existed for millions to tens of millions of years."

The interpretation comes from detailed analysis of two mudstones drilled by Curiosity earlier this year. The structure, chemistry and mineralogy of the sedimentary rocks were not alien.

"The whole thing just seems extremely earth-like," Grotzinger said.

The scientists presented their latest findings on Monday at a meeting of the American Geophysical Union in San Francisco and in a set of six articles published in the journal Science.

The surface of Mars today is frigid and arid, bombarded by sterilising radiation, but after it formed and cooled with the rest of the solar system about 4.5 billion years ago, it was initially a warmer and wetter place during its first billion years. Over the past decade, scientists have identified several sites on Mars that they think were once habitable.

In 2004, after the US space agency's rover Opportunity discovered evidence that the Martian places it was traversing had once been soaking wet, Steven Squyres, the mission's principal investigator, declared: "This is the kind of place that would have been suitable for life."

But that location would have been an extremely challenging environment for life to take hold - very salty and highly acidic. Later, the scientists said the soils had been soaked not so much by water as by sulphuric acid.

Nasa chose the 160 kilometre-wide Gale Crater as Curiosity's landing site because readings from orbit identified the presence of clay minerals, which form in waters with a neutral pH. Curiosity's instruments indeed detected clays in the two mudstones. The clays appear to have formed at the lake bottom, not swept down from the walls of Gale Crater, backing the idea that the water was not acidic.

Curiosity also measured carbon, hydrogen, oxygen, sulphur, nitrogen and phosphorus, elements that are critical for life on Earth, as well as iron and sulphur minerals that could have served as food for microbes.

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infinique
There are many signs that many civilizations once inhabited mars. It's just we refuse to accept this fact.
didier.newman.7
Then, is there fossils in Mars, life in other planets? But, isn’t the emergence and maintenance of life a process of radical contingency? That is, is a unique and unrepeatable past totally necessary? Or does life emerge through space like mushrooms when some conditions are present? So, how many conditions are necessary: three, four, trillions, infinite? Only one, water or any sort of God? Is God the word that means infinite conditions? Anyway, how did the life that emerge in a given conditions resist when switching to a different moment? How does life resist time itself, the effects of entropy? But, is it possible for human beings to recognise a simpler life than their own brain only? On the other hand, is it possible to recognise a complex life than their brain, is this the extra-terrestrial life that some people are searching unsuccessfully? However, is there an origin of life or would it be as finding a cut in the material history of the universe, an infinite void that human language patches now? Is there the same cut between life and death? What would you and me without this cut be? Along these lines, a serious-funny b-book, a public preview in goo.gl/rfVqw6 Just another suggestion for leisure, far away from dogmas or axioms.
 
 
 
 
 

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