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'Streams of water' on Mars

Last updated on: August 5, 2011 18:20 IST
This image shows warm-season features that might be evidence of salty liquid water active on Mars today

It is known that there are frozen water deposits on Mars. Now, it seems that there are seasonal streams of liquid water flowing across the surface of the Red Planet, say astronomers.

In fact, it was US space agency NASA which said that pictures taken from its Mars Reconnaissance Orbiter spacecraft showed finger-like features which may be flows of salty water spilling over the rims of craters.

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'Streams of water' on Mars

Last updated on: August 5, 2011 18:20 IST
Three images of the same location taken at different times on Mars show seasonal activity causing sand avalanches and ripple changes on a Martian dune

"NASA's Mars Exploration Programme keeps bringing us closer to determining whether the Red Planet could harbor life in some form, and it reaffirms Mars as an important future destination for human exploration," said NASA Administrator Charles Bolden.

MRO observations have tracked the seasonal changes in the dark, finger-like features appear and extend down Martian slopes late spring through summer, fade in winter, and return during the next spring.

'Streams of water' on Mars

Last updated on: August 5, 2011 18:20 IST
This image comes from observations of Newton crater, at 41.6 degrees south latitude, 202.3 degrees east longitude, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter

Some aspects of the observations still puzzle researchers, but flows of liquid brine fit the features' characteristics better than alternate hypotheses. Saltiness lowers the freezing temperature of water.

"These dark lineations are different from other types of features on Martian slopes," said MRO project scientist Richard Zurek of NASA's Jet Propulsion Laboratory in Pasadena, Calif.

'Streams of water' on Mars

Last updated on: August 5, 2011 18:20 IST
This photo shows many channels from 1 meter to 10 meters wide on a scarp in the Hellas impact basin. On Earth we would call these gullies. Some larger channels on Mars that are sometimes called gullies are big enough to be called ravines on Earth.
Images sent by MRO show dark, finger-like streaks appearing and extending down some Martian slopes during late spring through summer, fade in winter, and return during the next spring.

'Streams of water' on Mars

Last updated on: August 5, 2011 18:20 IST
This volcanic cone in the Nili Patera caldera on Mars has hydrothermal mineral deposits on the southern flanks and nearby terrains. The deposits are evidence for a past local environment that was warm and wet or steamy, possibly hospitable to microbial life

Lujendra Ojha and colleagues at the University of Arizona now claim that, if confirmed, the discovery could finally help establish whether life could be sustained on Mars.

"I was baffled when I first saw those features. We soon realised they were different from slope streaks that had been observed before. These were highly seasonal and we observed some of them had grown by more than 200 metres in a matter of just two Earth months," Jha said.

'Streams of water' on Mars

Last updated on: August 5, 2011 18:20 IST
Dunes of sand-sized materials have been trapped on the floors of many Martian craters. This is one example, from a crater in Noachis Terra, west of the giant Hellas impact basin

His colleague, Dr Alfred McEwen said the markings were "a mystery now, but a solvable mystery". "The best explanation we have for these observations so far is a flow of briny water, although this study does not prove that," he said.

The puzzling markings, which appear on several steep slopes south of the Martian equator, fade in the winter and reappear in the spring. While water may not be seen flowing above ground, the dark clusters could mean the water is underneath the surface, the Daily Express online reported.

'Streams of water' on Mars

Last updated on: August 5, 2011 18:20 IST
This image shows the west-facing side of an impact crater in the mid-latitudes of Mars' northern hemisphere

When the astronomers looked closer, their equipment failed to confirm the presence of water.

But Dr McEwen said this could be because the water quickly dries on the surface and happened not to be there when tests were carried out. Alternatively, it might exist but at shallow depths.

'Streams of water' on Mars

Last updated on: August 5, 2011 18:20 IST
The relatively bright, small ridges are ripples. From their study on Earth, and close-up examination by the MER rovers
The features could be the first definitive evidence of present day liquid water on the Red Planet.

If this turns out to be the case the sites may provide a promising hunting ground for signs of life, say the astronomers.

The findings have been published in the latest edition of the 'Science' journal