NASA finds evidence of liquid water on Mars

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In a paper published in this month’s prestigious Science journal, scientists from the NASA team studying data from the Mars Reconnaissance Orbiter (MRO) have announced the likely discovery of water flowing on the Red Planet.

The MRO is a satellite sent to Mars by NASA in 2005.  After almost 8 months journeying through interplanetary space, the satellite attained Mars orbit early in 2006.  Equipped with high resolution cameras, spectrometers, radar and other sensors, the satellite sends high quality images and other data to Earth.

In a recent set of photos from the southern hemisphere of Mars, scientists discovered dark streaks of material apparently flowing into a crater.  Numerous such streaks were identified, although they had been absent on previous occasions when the MRO had taken images of that area.  

Appearing as clusters of dark lines, the streaks fade in the Martian winter and reappear in the spring on several steep slopes of the crater.  The lines are between about 50cm (1.6ft) and 5m (16ft) wide but extend for hundreds of metres.

Dr Alfred McEwen, who lead the study of the Martian data, said: “The best explanation we have for these observations so far is the flow of briny water, although this study does not prove that.

“The problem is if water flows on Mars today it boils, it very rapidly evaporates into the atmosphere and freezes at some depth so unless you catch this right when it is active, and that is a very small area, you wouldn’t expect to see the water.

“Instead it is inference – all the characteristics we see suggest that it is volatile and the temperatures are right for this to be briny water.”

The latest images from the MRO can be seen on the NASA website, here.

Previously scientists have discovered tantalising evidence that water once existed on Mars, and have already discovered water ice in the polar regions of the planet where there is also ‘dry ice’, or frozen carbon dioxide.  Some years ago the MRO sent data which suggested that a liquid had flowed over the Martian surface at some recent point in the past, but this is the first time that evidence has been discovered of liquid water in flow on the planet’s surface.

During a NASA press conference yesterday, geophysicist Philip Christensen said: “It hasn’t been in question for some time now that there’s ice on Mars.  What makes these new observations so interesting is that they occur at much lower latitudes where temperatures are much warmer and where it’s actually possible for liquid water to exist.”

The discovery of liquid water gives a massive boost to the possibility that life may exist on Mars.  All life on Earth depends on water in its liquid state.  Mars is seen as one of the most likely candidates in our solar system for harbouring life.