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Mars : not a dead planet ?

 
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Kalinoux
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MessagePosté le: 25/01/2009 21:47:23    Sujet du message: Mars : not a dead planet ? Répondre en citant

Arrow Methan on Mars

Discovery of Methane Reveals Mars Is Not a Dead Planet WASHINGTON -- A team of NASA and university scientists has achieved the first definitive detection of methane in the atmosphere of Mars. This discovery indicates the planet is either biologically or geologically active.

The team found methane in the Martian atmosphere by carefully observing the planet throughout several Mars years with NASA's Infrared Telescope Facility and the W.M. Keck telescope, both at Mauna Kea, Hawaii. The team used spectrometers on the telescopes to spread the light into its component colors, as a prism separates white light into a rainbow. The team detected three spectral features called absorption lines that together are a definitive signature of methane.

"Methane is quickly destroyed in the Martian atmosphere in a variety of ways, so our discovery of substantial plumes of methane in the northern hemisphere of Mars in 2003 indicates some ongoing process is releasing the gas," said Michael Mumma of NASA's Goddard Space Flight Center in Greenbelt, Md. "At northern mid-summer, methane is released at a rate comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, Calif." Mumma is lead author of a paper describing this research that will appear in Science Express on Thursday.

Methane, four atoms of hydrogen bound to a carbon atom, is the main component of natural gas on Earth. Astrobiologists are interested in these data because organisms release much of Earth's methane as they digest nutrients. However, other purely geological processes, like oxidation of iron, also release methane.

"Right now, we do not have enough information to tell whether biology or geology -- or both -- is producing the methane on Mars," Mumma said. "But it does tell us the planet is still alive, at least in a geologic sense. It is as if Mars is challenging us, saying, 'hey, find out what this means.' "

If microscopic Martian life is producing the methane, it likely resides far below the surface where it is warm enough for liquid water to exist. Liquid water is necessary for all known forms of life, as are energy sources and a supply of carbon.

"On Earth, microorganisms thrive about 1.2 to 1.9 miles beneath the Witwatersrand basin of South Africa, where natural radioactivity splits water molecules into molecular hydrogen and oxygen," Mumma said. "The organisms use the hydrogen for energy. It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon. Gases, like methane, accumulated in such underground zones might be released into the atmosphere if pores or fissures open during the warm seasons, connecting the deep zones to the atmosphere at crater walls or canyons."

It is possible a geologic process produced the Martian methane, either now or eons ago. On Earth, the conversion of iron oxide into the serpentine group of minerals creates methane, and on Mars this process could proceed using water, carbon dioxide and the planet's internal heat. Although there is no evidence of active volcanism on Mars today, ancient methane trapped in ice cages called clathrates might be released now.

"We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tons of methane," said co-author Geronimo Villanueva of the Catholic University of America in Washington. "The plumes were emitted during the warmer seasons, spring and summer, perhaps because ice blocking cracks and fissures vaporized, allowing methane to seep into the Martian air."

According to the team, the plumes were seen over areas that show evidence of ancient ground ice or flowing water. Plumes appeared over the Martian northern hemisphere regions such as east of Arabia Terra, the Nili Fossae region, and the south-east quadrant of Syrtis Major, an ancient volcano about 745 miles across.

One method to test whether life produced this methane is by measuring isotope ratios. Isotopes of an element have slightly different chemical properties, and life prefers to use the lighter isotopes. A chemical called deuterium is a heavier version of hydrogen. Methane and water released on Mars should show distinctive ratios for isotopes of hydrogen and carbon if life was responsible for methane production. It will take future missions, like NASA's Mars Science Laboratory, to discover the origin of the Martian methane.

The research was funded by the Planetary Astronomy Program at NASA Headquarters in Washington and the Astrobiology Institute at NASA's Ames Research Center in Moffett Field, Calif. The University of Hawaii manages NASA's Infrared Telescope Facility.



Other links to visit :

Arrow Methan on MArs_2
(video of an interview of an expert from NASA available)

Arrow Mars : detailed description of the planet.

Kalinoux Respect
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MessagePosté le: 25/01/2009 21:47:23    Sujet du message: Publicité

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Kalinoux
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Inscrit le: 01 Sep 2006
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J'accepte La charte: Oui j'ai lu et pris connaissance de la charte, j'e l’accepte et je m’engage à la respécter

MessagePosté le: 25/01/2009 22:44:04    Sujet du message: Mars : not a dead planet ? Répondre en citant

Another link, dealing with the same topic here Arrow The Sun

Citation:
Nasa reveals life on Mars


Citation:
Life is responsible for more than 90 per cent of the Earth’s atmospheric methane.

Experts believe there is a good chance that organisms produced the gas emissions - as large as some of those seen on Earth - on Mars too.


Citation:
Scientist Michael Mumma of NASA’s Goddard Space Flight Center said: “This raises the probability substantially that life was there or still survives at the present.

“We think the probability is much higher now based on this evidence.”

The bugs that made it may have vanished millions of years ago, leaving the methane frozen under the planet’s surface.

But another possibility is that some hardy organisms still survive on the Red Planet, living underground without sunlight and using hydrogen from water for energy. Similar microbes exist on Earth.

Methane produced by the action of water on hot carbon bearing rocks, as occurs in volcanic regions on Earth, is the alternative explanation.

Whatever the source is, scientists agree that something is replenishing the methane.

The find is seen as exciting new evidence that Martian microbes are still alive today.

Some scientists reckon methane is also produced by volcanic processes. But there are NO known active volcanoes on Mars.

Furthermore, Nasa has found the gas in the same regions as clouds of water vapour, the vital “drink” needed to support life.


Citation:
Experts speculate that the methane is being emitted as a waste product by organisms called methanogens living in water beneath underground ice.

And they would have to be alive today because the methane would otherwise have been lost from the Martian atmosphere.


Citation:
John Murray — a member of the Mars Express European space probe team — believes the mini-Martians may be in a form of suspended animation and could even be REVIVED.

He has found overwhelming evidence of a vast frozen ocean beneath the dust near the Martian equator where simple life could have thrived as microbes.

Today’s briefing will feature a star panel of Mars experts headed by Michael Meyer, chief scientist for Nasa’s Mars programme.

UK Mars expert Professor Colin Pillinger believes the methane can only point to the presence of life on the planet.

His ill-fated Beagle 2 probe was carrying a laboratory that would have looked directly for such signs of life when it crashed on Christmas Day 2003.


Citation:
Prof Pillinger told The Sun last night: “Methane is a product of biology. For methane to be in Mars’ atmosphere, there has to be a replenishable source.

“The most obvious source of methane is organisms. So if you find methane in an atmosphere, you can suspect there is life.

“It’s not proof, but it makes it worth a much closer look.”

Nasa’s findings confirm studies by Europe’s Mars Express probe, which has been orbiting the planet for five years and also reported signs of methane in 2004.

Britain’s top space expert Nick Pope last night hailed the new evidence of life as “the most important discovery of all time”.

He said: “What could be more profound than to know it’s not just us out there?

"We’ve really only scratched the surface — it’s an absolute certainty that there is life out there and we are not alone.

“If there is life on Mars then the logical conclusion is that there must be life elsewhere too.

“If it’s happened here on Earth, then why shouldn’t it happen anywhere? The implication is this is a universal law.

“Mars is very similar to Earth. It’s about the same size, it’s a rocky inner planet.

“Most scientists believe it probably has liquid water which is almost universally agreed as the pre-requisite for life. I am certain there is other life in the Universe and, most likely, intelligent life.”

The Red Planet has gripped the public imagination for more than a century as a possible home for aliens.

But life could not survive on its surface because, unlike the Earth, Mars has no magnetic shield to protect it against deadly sun radiation.

The planet resembles our own in many ways. It is made of rock, it has an atmosphere and weather systems.

Although much smaller with a diameter of around 4,222 miles, Mars’ day is just 40 minutes longer than ours and its tilted axis gives it seasons.

Water has been found in the form of buried ice and scientists believe that two billion years ago, Mars was covered with liquid oceans.

Proof that water is still on Mars came in 2007 when Mars Express used ground-piercing radar to study the region around the planet’s South Pole.

Nasa’s latest lander Phoenix dug up chunks of Martian ice last year. It swiftly evaporated into the thin atmosphere.

Nasa have controversially hit the headlines before for claiming evidence for Martians.

In 1996, they said they had discovered fossilised organisms in a meteorite from the planet.

But other scientists were sceptical.



Kalinoux
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MessagePosté le: 27/05/2017 15:46:33    Sujet du message: Mars : not a dead planet ?

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