Strong proof that there is water on Mars as Curiosity rover discovers rounded pebbles that look like those on Earth's riverbeds

By EDDIE WRENN

Scientists exploring Mars have discovered that water once flowed in streams several feet deep, fuelling speculation that the planet could have once supported life.

The news, which has left top NASA scientists 'excited', comes thanks to photographs of bedrock beamed back from the red planet by the Curiosity rover.
There have been previous signs that water existed on Mars long ago, but the images released on Thursday showing pebbles rounded off, probably by water, offered the most convincing evidence so far of an ancient streambed which could have been waist-deep.

Carved out: These rounded rocks on Mars were probably caused by running water, according to scientists

There was 'a vigorous flow on the surface of Mars,' said chief scientist John Grotzinger of the California Institute of Technology. 'We're really excited about this.'
The discovery did not come as a complete surprise. NASA decided to land Curiosity inside a spot near the Martian equator, Gale Crater, because photos from space hinted that the spot possessed
a watery past.
What has surprised scientists are the mild temperatures recorded by the weather station on board Curiosity.
On more than half the days Curiosity has been exploring Mars, the daytime temperature has been above 0°C, according to the Remote Environment Monitoring Station (REMS).

Exciting: The discovery, beamed back by the Curiosity rover, makes it more likely that Mars once supported life

Mars has reached above 6°C - and it may even reach the 20°C as the Martian 'summer' continues.
Mind you, that's little consolation during the night, when the temperature plummets to -70C, which is even colder than average winter temperatures on Antartica.
Dr Felipe Gómez of the Centro de Astrobiología in Madrid said: 'That we are seeing temperatures this warm already during the day is a surprise and very interesting.
'It’s very early days and we are only now being able to test our models against REMS observations. If this warm trend carries on into summer, we might even be able to foresee temperatures in the 20s [Celsius] – and that would be really exciting from a habitability point of view.'
The rising temperatures could also mean liquid water somewhere close to Mars's surface - but Gomez added: 'It’s too soon to tell whether that will happen or whether these warm temperatures are just a blip.'

Spot the difference: The Martian landscape, left, is similar to bedrock formations on Earth, right

REMS pressure sensors have also been recording slightly higher pressures than expected.
In winter, Mars becomes cold enough for carbon dioxide at the poles to freeze, forming seasonal ice caps and carbon dioxide snowfalls - and removing it from the atmosphere means atmospheric pressure varies through the year.

Procession: This overhead image shows the route Curiosity is currently travelling across Mars

The six-wheeled rover safely landed on 5 August after a nail-biting plunge through the Martian atmosphere. It is on a two-year, US$2.5billion mission to study whether the Martian environment
could have supported life.

Mars is now a frozen desert with no hint of water on its radiation-scarred surface, but geological studies of rocks by previous missions suggest the planet used to be warmer and wetter.

source: dailymail