An orbiting spacecraft has sent back new evidence for the presence of water on Mars. Scientists long have debated whether water flowed on the red planet, with evidence increasing in recent years. The presence of water would raise the possibility of at least primitive life forms existing there. Images from a camera aboard NASA's Mars Reconnaissance Orbiter show alternating layers of dark- and light-toned rock in a giant rift valley.Within those deposits are a series of linear fractures, called joints, that are surrounded by "halos" of light-toned bedrock, according to researchers from the University of Arizona.Their findings, published in Friday's edition of the journal Science, were being presented at the annual meeting of the American Association for the Advancement of Science in San Francisco.Lead author Chris H. Okubo said the "halos" indicate areas where fluids, probably water, passed through the bedrock. Minerals in the fluid strengthen and bleach the rock, he said, making it more resistant to erosion than other areas."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," Okubo and co-author Alfred S. McEwen reported in the paper.

The researchers also said that layered outcrops can indicate cycles with materials deposited by regular episodes of water, wind or volcanic activity.Just last December scientists reported evidence that water may be flowing through Mars' frigid surface. Images from Mars Global Surveyor showed changes in craters that provide the strongest evidence yet that water moved through them as recently as several years ago, and is perhaps doing so even now.The Surveyor previously had spotted tens of thousands of gullies that scientists believed were geologically young and carved by fast-moving water coursing down cliffs and steep crater walls. Scientists decided to retake photos in a search for evidence of recent activity.

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I'm wondering if an advance race once lived on Mars and then was wiped out? Maybe the planet is now just starting to revive itself and is showing these signs.

^ Aparantally, when the solar system was a couple of 100,000 years old, mars was once like earth, with trees and flowing water and probabally animals, but the orbits around the sun were different (or something) and mars gradually got further and further away and turned into what it is now. I can't remember what I saw it off but it was a documentary of some sort.

Strange. If Mars was once like earth but as it got further away from the sun, it became a planet with no sign of life despite if Trees were there - which counts as life. As it's 'further away' and there's no detectable life now, how do you explain why there's life on Earth which is further away but none on Mars? If it's just life not geting use to the changes, how can that be? As it got further away, it would probably take thousands or millions of years to be where it is, surely life was able to adapt within that time to colder climates - unless they're evolution is different to ours, they might be slower! But then what if life never existed there? So many questions, so mant idears!

What it probably was that Mars had a thicker atmosphere at one time, that would have let water exist and the temperatures would have been more earthlike at that time. Water vapor is a greenhouse gas and along with the abundant Martian carbon dixoide, it would have warmed the planet to suitable temps.

If Mars is coming back to life, then we need to sit back and learn..watch what happens.

However, after seeing the dense atmosphere of Titan, Mars could have held an appreciateable atmosphere that was not unlike earth. although the temps might have been about 20 degrees F cooler. More so like early spring or late fall on earth.

What is interesting is the cloud formations of water vapor that still exist.

Mars environment is pretty similar to the Earth's. I wouldn't be surprised if a life of some sort existed there (or exists now).
Colonization of Mars by humans is not only a topic of science fiction; it's being thoroughly discussed by scientists. The moon is also a favorable place for colonization if not for its low gravitational state.

I don't understand why anyone would want to live on the Moon. That's just silly. I don't care if there's a million wars raging here on Earth, we have something the moon will never have: LANDSCAPES. I would definitely get tired of that gray, cratery rock. I wouldn't mind visiting outer space but not living on someplace like the Moon.

What more evidence do we need? And if there are small life-forms on Mars, then what?

The depletion of the atmosphere on mars was due to solar flares (according to the discovery channel). The reason that the earth is not affected like mars was (according to the discovery channel LOL), is because of our iron core.