Is there life on Mars?

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Triumphant return to the Red Planet - now NASA will probe what lies beneath

May 27, 2008 -- At first, the probe checked itself over, taking snapshots of its dusty feet and freshly unfurled solar arrays, ensuring all was present and correct following its 422m-mile journey and high-speed descent on to the northern plains of Mars in the early hours of yesterday.

Then the real work began. The robotic arm flexed and swivelled, bringing the camera up and around to gaze at the alien landscape. Two hours later, NASA's mission controllers had been sent the first pictures ever to be taken within the arctic circle of the red planet.

The $420m (£212m) Phoenix mission, which settled on Mars at 00.53 BST yesterday, represents a major milestone in NASA's exploration of the solar system and its search for evidence of life elsewhere. Not since the Viking landers touched down in 1976 has a probe landed softly on the planet, using rocket thrusters to slow its descent. More significantly, Phoenix is expected to become the first spacecraft to touch water on another planet.

At NASA's Jet Propulsion Laboratory in California last night, the final moments before landing were tense, but at every step the Phoenix probe matched or exceeded expectations. As it hurtled into the atmosphere, engineers foresaw a communications blackout as the searing plasma around the probe's heat shield blocked their radio link. When the moment came, the probe kept in touch all the way down, settling at a near-perfect 0.25-degree angle in the Vastitas Borealis, an ancient plain near the north pole.

"In my dreams, it couldn't have gone as perfectly as it did," said Barry Goldstein, the project manager on the Phoenix mission. "I'm in shock. Never in rehearsal did it go so well."

Yesterday, NASA engineers began analysing the first of the images, some showing the intriguing polygonal patterns that scar the Martian arctic. One of the probe's mission tasks is to dig beneath the frigid surface to collect water ice and soil, which will be analysed by the probe's onboard laboratory. Mission controllers will be looking for signs of organic compounds in the water that could indicate that the now harsh environment was once hospitable, and even habitable.

"We see the lack of rocks that we expected, we see the polygons that we saw from space, we don't see ice on the surface, but we think we will see it beneath the surface," said Peter Smith, the principal investigator on the mission at Arizona University.

The landing marks the US space agency's first return to Mars since its twin rovers, Spirit and Opportunity, touched down in January of 2004.

"This is the first chance we have had to actually collect and analyse water on the Red Planet," said Keith Mason, head of Britain's Science and Technology Facilities Council.

"If we find water ice below the Martian surface we may also be able to find evidence of past life on the planet."

Over the next eight days, the probe will continue to take measurements of the Martian atmosphere and soil before using its two-metre-long robotic arm to dig down to what lies beneath. Onboard cameras and a weather station will record information about the probe's changing environment as night turns to day and the Martian seasons turn. The mission is expected to last three months, after which the arrival of winter will see light levels fall too low to replenish the Phoenix probe's batteries.

"We're all so relieved that Phoenix has managed to land safely," said Tom Pike, head of the UK Phoenix team at Imperial College London. "The descent and landing phase of the mission is one of the most tricky and hazardous. It's great to have made it down in one piece and now we can get to work uncovering more of the Red Planet's secrets."

The London team developed tiny silicon sheets that will hold dust and soil samples for the probe to examine with high-resolution microscopes.

Another of the probe's tasks is to monitor changes in the polar weather and how it interacts with the land and atmosphere above. In the arctic summer on Mars, scientists believe water vapour is released from ice at the polar caps and into the atmosphere.

David Catling, a scientist on the team from Bristol University, said: "Our priority now is to find out if there is ice below the dirt and whether it got there recently, or it is a frozen remnant from an ancient time when liquid water may have rippled across this part of Mars."

As the name suggests, the 350kg Phoenix probe arose from the embers of previous Mars missions, themselves failed or shelved in 1999 and 2001, but useful for their spare parts, from which the spacecraft was put together.

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D’après une étude parue dans Science :
Le méthane serait un signe de vie sur Mars

Samedi 14 Février 2009 -- On ne s’attendait pas à la présence du méthane sur la planète Mars, compte tenu de son atmosphère oxydative. Mais on vient de détecter qu’il est en train d’être libéré. La photolyse (réaction chimique dans laquelle un composé chimique est décomposé par la lumière), à elle seule, pourrait éliminer le méthane sur une période de 300 à 600 ans, explique à El Watan l’astrobiologiste Michael Mumma, du Goddard Center for Astrobiology de la Nasa.

Nous avons utilisé des spectrophotomètres infrarouges à haute dispersion montés sur des télescopes terrestres pour mesurer simultanément le méthane et la vapeur d’eau sur Mars. Nos résultats requièrent une période beaucoup moins courte et donc le processus de son élimination est plus efficace d’un facteur de 100. En définitive, nous avons prouvé l’existence du méthane sur Mars et montré qu’il varie spatialement selon les saisons. Ceci implique une libération récente et, par voie de conséquence, active. » Le méthane qui est train d’être libéré pourrait avoir été produit récemment ou il y a de nombreuses années. Autre hypothèse : la géochimie ou la biologie pourrait être à l’origine de ces émissions, car on sait que le méthane est principalement généré sur Terre par des phénomènes biologiques. Et Mumma de préciser : « Nous devons, tout de même, faire la différence entre production et libération. Le méthane, que nous avons détecté, pourrait avoir été produit il y a de cela longtemps, puis stocké dans la glace.

En d’autres termes, la production serait ancienne, mais la libération est actuelle. » Un tel phénomène rendrait possible la vie sur Mars. Chaque découverte concernant la planète rapproche davantage les chercheurs de la compréhension de cette planète. Après avoir suivi la piste de l’eau, toutes les agences spatiales essaient d’en savoir plus sur cette activité du méthane et sa possible origine. « La stratégie de recherche a été élargie pour inclure d’autres gaz qui pourraient favoriser la vie ou au contraire, la rendre impossible. Le laboratoire Science de Mars, lancé par la NASA en 2011, se focalisera sur les complexes organiques des roches, et bien évidemment le méthane et d’autres gaz. »

[Abdelmoumene]

Nasa said its Mars Reconnaissance Orbiter spotted ice at five new Martian craters, likely kicked up by meteor impacts.

'This ice is a relic of a more humid climate from perhaps just several thousand years ago,' said Shane Byrne of the University of Arizona. 'This is a real water resource.'

The discovery at the satellite's mid-latitudes is much further from the poles than was previously thought.
This, argues a report in Scientific American, would provide supplies for colonists to use on landing.


The news comes a day after it was also revealed that large quantities of water had been found on the surface of the Moon.

It means a manned base on the Earth's satellite could now become a reality within 20 years.

The discovery increases the chances of humanity living on the lunar surface inside protective domes, mining the rocks and dust for water to drink and power spacecrafts.

The scientific discovery made by the Indian lunar mission Chandrayaan-1 was announced by Nasa today.
'Widespread water has been detected on the surface of the Moon. None of us had expected this 10 years ago,' Nasa's Carle Pieters said.

Dr Jessica Sunshine, one of the researchers who found the water, said: 'It's sort of just sticking on the surface. We always think of the Moon as dead, and this is sort of a dynamic process that's going on.'

Ten years ago, scientists found traces of water lying in the shadowy craters at the Moon's poles.

The latest announcement comes two weeks before a Nasa probe will smash near the Moon's south pole to see whether it can kick up buried ice.

The discovery, with three studies being published in the journal Science today and a Nasa briefing, could refocus interest in the moon.

The appeal of the Moon waned after astronauts visited 40 years ago and called it 'magnificent desolation'.

The discovery confirms what two other space probes have found, namely that the chemical signs of water are all over the Moon's surface.

It is not enough moisture to foster homegrown life on the Moon. But if processed in mass quantities, it might provide resources - drinking water and rocket fuel - for future Moon-dwellers, scientists say. The water comes and goes during the lunar day.

Dr Sunshine said a two litre bottle of lunar earth would only provide enough water to fill the pipette of a medicine bottle.

And Nasa's Rob Green told a press conference tonight: 'Even the driest deserts on Earth have more water than at the poles of the Moon.'

When Apollo astronauts first returned from the Moon in 1969, they brought back souvenirs in the form of rocks to be used for analysis, and one of the chief questions was if there was water in lunar rocks and soils.

However, most of the boxes containing the lunar samples leaked which led scientists to assume traces of water found came from Earth air that had entered the containers.

They assumed that, outside the possibility of ice at the poles, there was no water on the Moon. Now 40 years later, this old assumption has been overturned.

A lunar scientist familiar with the findings said: 'This is the most exciting breakthrough in at least a decade. And it will probably change the face of lunar exploration for the next decade.'

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New images show evidence of lakes on Mars, say scientists

January 4, 2010 -- Lakes of liquid water existed on Mars at a time when the planet was previously thought to be a frozen desert, new satellite images have shown. A team of British-led scientists now believes 12 mile-wide lakes of melted ice were dotted around parts of the Martian equator 3 billion years ago. No one had expected to find evidence of a warm, wet climate capable of sustaining surface water on Mars during this period of the planet's history, known as the Hesperian epoch. Lakes, seas and rivers may have existed on the planet at an earlier time between 3.8 billion and four billion years ago, experts believe. But before the Hesperian Epoch the planet was assumed to have lost most of its atmosphere and turned cold and dry. The new high-definition images come from the American space agency Nasa's Mars Reconnaissance Orbiter spacecraft. The dry lakes will be good places to go to look for signs of now-extinct microbial life, say scientists. Dr Nicholas Warner, from Imperial College London, whose team analysed the images, said: "Most of the research on Mars has focused on its early history and the recent past. Scientists had largely overlooked the Hesperian Epoch as it was thought that Mars was then a frozen wasteland. Excitingly, our study now shows that this middle period in Mars' history was much more dynamic than we previously thought." The British researchers, including scientists from University College London, examined several flat-floored depressions located above Ares Vallis, a giant gorge that runs for 1,242 miles across the Martian equator. Their origin has been a puzzle, but experts had thought they were caused by the ground sinking when ice locked in the soil evaporated and vanished without first turning liquid. The new study revealed for the first time that small sinuous channels connected the depressions. Their appearance suggests they were created by lakes on higher ground bursting their banks and water draining into lower-lying lakes.

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'Compelling' evidence of life on Mars: NASA

April 29, 2010 -- Earthlings, you are not alone. Scientists from NASA have reportedly found “compelling” new evidence of life on Mars. A special mission to the Red Planet has revealed the presence of a form of pond scum — the building blocks of life as we know it, reports the Sun. Experts from NASA put forward the claim as they unveiled the results of the recent Opportunity and Spirit probes, which were sent millions of miles through the solar system to discover signs of extraterrestrial life. The researchers say that the results are so promising that the agency has already planned a host of other missions to discover whether there is extraterrestrial life in the universe. The recent missions have gathered evidence of sulphates on Mars, a strong indication there is water on the planet and, therefore, life. Previous missions to Mars have concluded there is probably water on the planet. But the NASA researchers said the recent missions have gone further than any others in proving there is life on Mars. They were particularly excited about the discovery of a sulphate called gypsum which, it has emerged recently, is found in large quantities among fossils in the Mediterranean. "One, thanks to Opportunity and the Rovers and orbital imaging it is clear that there are literally vast areas of Mars that are carpeted with various sorts of sulphates, including gypsum," the Sun quoted Bill Schopf, a researcher at the University of California in Los Angeles, as saying. Almost 30 NASA missions to discover life in space - including one to bring back rocks from Mars — have already been planned.