Crater shows Mars's atmosphere must once have been thicker - could have shrouded a watery world

Crater shows that Mars's atmosphere must once have been thicker and could have shrouded a watery world

• Crater on surface 'proves' Mars must have once had thicker atmosphere
• One of reasons water doesn't flow on Mars is atmosphere is 1% as thick as Earth's
• Adds to growing body of evidence Mars was once a watery world like Earth

Valles Marineris on Mars - which some scientists believe may have been carved by glaciers. A growing body of evidence points to the fact that water once flowed on the planet

When life was just beginning to emerge on Earth, nearby Mars could also have been a watery world shrouded in a dense atmosphere that could have supported life.

One of the reasons water no longer flows on Mars's surface is because its atmosphere is less than 1% of the density of the Earth's.

But Professor Josef Dufek, of Georgia Tech university, looked at a crater left by a rock fragment around 3.5 billion years ago, found by Mars Rover Spirit - and realised from the depth of the crater that the atmosphere must once have been much thicker.

‘Our study is consistent with growing research that early Mars was at least a transiently watery world with a much denser atmosphere than we see today.

The mosaic image captured by the Mars Express orbiter is colour-coded for elevation, showing the valleys and cliffs thought to have been carved out by ancient floods on the surface

An earlier study found gypsum on Mars - indicating there was once water on Mars and the possibility of life.

Journal Science reports that the gypsum could only have been formed in water below 60 c and writes: ‘That means that conditions conducive to life once existed on the edge of the crater.’

Daily Mail

The Tiu Vallis region on the surface is dotted with buttes, valleys and craters thought to have been carved out by energetic masses of liquid in the distant past

I'm not really sure why this is news, I thought it was common knowledge that at *one* point Mars had an atmosphere comparable to Earth's. And that the poles contain enough ICE that if it were to melt, it would leave the Martian surface about 11 feet under water.

Not only that but the features alone indicate flowing water at one point.

And I also thought it's still possible that microbial life may still exist under the surface of the planet, in moist soil.

The extent to which we've physically investigated Mars, is akin to us dropping a digital camera into the Sahara desert. It's not in any way in indication of the planets total.

Also, there is speculation that as the planet itself shifts about 45 degrees on it's polar axis every 5 million years, that perhaps 5 million years ago the planet was teaming with microbial life (or even further, evolved life) but now then it shifted axis, and everything froze again. Another 5 million years, it may be once more teaming with life.

We don't know. We're but a spec in the lifeline of our solar system. We would know just as little by looking at a grain of sand and determining it was always a single grain of sand, and never once part of a mountain...

Sure we do not *know*, but I thought it was still evident by observation alone that water once flowed on the surface of Mars.
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