Mars was 'once habitable'

[Logan13]

Mars was 'once habitable'
February 16, 2007
http://theaustralian.news.com.au/sto...rom=public_rss

SPECTACULAR images from a Martian "grand canyon" have revealed signs of abundant ground water that may have flowed through cracks in the rock many millions of years ago.
The pictures are more evidence that Mars was once a habitable planet with breathable air, streams, lakes, rain - and possibly life.

They were obtained by a powerful camera on the American space agency NASA's Mars Reconnaissance Orbiter spacecraft which is capable of resolving surface features 12cm across.

Last northern autumn, scientists turned the HiRISE (High Resolution Imaging Science Experiment) camera onto the Candor Chasma, one of several canyons that make up the great Martian rift valley called Valles Marineris.

Transplanted on Earth, the rift valley just south of the Martian equator would stretch across the US.

In places, it is six to seven times deeper than the Grand Canyon - the deepest fissure on any planet in the Solar System.

The first detailed images produced of this dramatic landscape surprised and excited the NASA experts.

They show exposed layers of dark and light rock, crossed by sand dunes.

Within the layers are a series of linear fractures, called joints, surrounded by "halos" of light-coloured bedrock.

Scientists say the "halos" are caused by chemical bleaching and are clear evidence that fluid, most likely water, once flowed through the fractures that extend up to several kilometres.

The findings were presented at the start of the world's biggest science conference, the annual meeting of the American Association for the Advancement of Science, being held in San Francisco. They also appear today in the AAAS journal Science.

Professor Alfred McEwen and Dr Chris Okubo, who analysed the images at the University of Arizona in Tucson, wrote: "On Earth, bleaching of rock surrounding a fracture is a clear indication of chemical interactions between fluids circulating within the fracture and the host rock."

The fluid was very likely to have been water, said the scientists. This could be confirmed by direct analysis of the rock composition using instruments carried on future Mars rovers.

HiRISE, which takes pictures with different colour filters, has also captured stunning images of other regions on Mars. They include Becquerel Crater in Arabia Terra, a densely cratered area in the northern hemisphere, where rock layers can also be seen.

Fluid processes similar to those that shaped Candor Chasma are thought to be evident in Victoria Crater, now being explored by the NASA Mars rover Opportunity.

The rover has been roaming the Martian surface for three years.

HiRISE images of the crater, which sits on a vast plain just south of the Martian equator, revealed structures along the eastern slopes that may have been formed by water flowing through fractures.

Layered deposits have intrigued scientists since they were first discovered by the Mariner 9 and Viking orbiters in the 1970s.

"The origin, history and nature of the light-toned layered deposits are of great interest," said Professor McEwen.

"There has been lots of debate about the significance of these materials."

Recent Mars missions have produced a wealth of evidence that long ago, perhaps when life was just emerging on Earth, the planet had an active water cycle.

There have also been suggestions of water flowing much more recently on Mars. Mars Global Surveyor, another NASA orbiter, has found evidence that water might have flowed briefly in two Martian gullies within the past few years.

A huge frozen sea, covered and protected by a thin crust of dust and volcanic ash, is also believed to exist in the equatorial Elysium region.

[Kärnfysikern]

Hope its right. We need to put some serious machines or humans on that planet. Finding fossiles of early life on mars would be the biggest discovery ever. We would know we are not alone and that life is abundant everywhere.

[singern]

I have always been a subscriber to the idea that life must exist, or did exist , or will exist elsewhere, if only based on the vastness of the galaxy, and indeed the universe. So why not on Mars, its as likely as anywhere else.

[Kärnfysikern]

I have always been a subscriber to the idea that life must exist, or did exist , or will exist elsewhere, if only based on the vastness of the galaxy, and indeed the universe. So why not on Mars, its as likely as anywhere else.

Yeah. It happened on earth so no reason to belive it wont have happened in a billion other places.

Im still pissed of that NASA canceled the icy moon orbiter that was suposed to checkout europa. If there is a prime place for life it surely is that moon.

[Logan13]

Yeah. It happened on earth so no reason to belive it wont have happened in a billion other places.

Im still pissed of that NASA canceled the icy moon orbiter that was suposed to checkout europa. If there is a prime place for life it surely is that moon.

politics has no place in science. I often do not understand the reasoning behind NASA's decisions.

[bigmike8585]

that would definatley be hell of a discovery if we found serious life forms there

[Kärnfysikern]

politics has no place in science. I often do not understand the reasoning behind NASA's decisions.

Unfortunaly the reason now was that there wasnt enough money for both science projects and the new moon and mars project. Instead of increasing the NASA budget to make room for the moon and mars plans the bush admin just forced NASA to switch funds.

Its a shame because Im obviously a big supporter of both manned flights and robotic scientific missions. But at this point Id say the robotic missions are more important, cutting funds for them was moronic. Especialy since the money wont be enough for the manned flights anyway. Chanses are america wont go to the moon again soon and there will be no science done.

I aint holding my breath for europe to increase ESA fundings either....