Mars' entire surface was shaped by water

The whole of Mars' surface was shaped by liquid water around four billion years ago, say scientists.


Signs of liquid water had been seen on southern Mars, but the latest findings reveal similar signals in craters in the north of the Red Planet.

The team made their discovery by examining data from instruments on board Europe's Mars Express and Nasa's Mars Reconnaissance Orbiter.

They report the findings in the latest issue of the journal Science.

John Carter, of the University of Paris, led the team of France- and US-based scientists.

"Until now, we had no idea what half Mars was made of in terms of mineral composition".

"Now, with the Esa and Nasa probes, we have been able to get a mixture of images and spectral information about the composition of the rock."

He explained that these instruments had revealed clay-type minerals called phyllosilicates - "the stuff you would find in mud and in river beds."

"It's not the species of mineral itself that's important," said Dr Carter, "it's more the fact that the minerals contain water.

"This enhances the picture of liquid water on Mars."

Liquid rock

Previously, researchers have seen similar signs of water in the highlands of southern Mars in rocks that are up to four billion years old. But in the northern part of the planet, more recently formed rocks have buried the older geology.

The prevailing theory for why this is, is that a giant object slammed into northern Mars, turning nearly half of the planet's surface into the Solar System's largest impact crater.

Dr Carter explained that this meant a thick veneer of younger rock covered the older geology, "so the craters are the only way of accessing the older stuff".

But the craters are relatively small and more difficult for the orbiting probes to take measurements from.

"There's also ice and dust coverage in the north of the planet, making it harder to get signals from these craters," said Dr Carter.

The new findings suggest that at least part of the wet period on Mars, that could have been favourable to life, extended into the time between that giant impact and when volcanic and other rocks formed an overlying mantle.

This indicates that, 4.2 billion years ago, the planet was probably altered by liquid water on a global scale.

But Dr Carter said that the findings did not paint a picture of huge Martian oceans.

"It was probably a very dry place," he said. "But we're seeing signals of what were once river beds, small seas and lakes."

The Girl Who Never Ages

A young girl is under the scrutiny of scientists who say she may be one of the most important finds in the often sought fountain of youth.  The girl has been alive for seventeen years, but still looks and behaves like a one-year-old child.  She weighs 16 lbs and is only 30 inches in height.  Most people who see her say Brooke Greenberg is only a toddler.  But Brooke Greenberg is almost old enough to vote.  Scientists say the child is suffering from a rare genetic mutation.  And if scientists map her genome as they are hoping to do, they may find out why.

Brooke, age 17

When many scientists look at Brooke Greenburg, they see an opportunity to discover why we age.  When her mother sees her, she sees the girl who will never grow up - literally.  Researchers at the University of South Florida School of Medicine, led by Richard Walker, have suggested that the girl's rare condition is an opportunity for the team to study something that they have been attempting to uncover for years: why we age.  There are several theories, but the actual mechanics behind the aging process are often unclear or misleading.  "If we can compare her genome," Walker says, "to the normal version then we might be able to find those genes and see exactly what the do and how to control them."

Age is a matter that all humans have to come to terms with at some point in their lives.  We are born, we reach a peak age, and then we begin gradually to deteriorate before we die.  But what about a world where we didn't age?  That's the question several scientists are proposing.  If genes could be studied accurately, then not only could the aging process potentially be halted, there are some who suggest it could even be (in some ways) reversed.  Of course this field of research is still new, and there are a thousand different avenues of research that could help the whole world.

Meanwhile, life for Melanie and Howard Greenberg goes on in the suburb where they live.  It's a struggle as they continue to help Brooke through her life as an eternal toddler, changing her, rocking her to sleep, and attempting to teach her to speak.  Brooke crawls, smiles, and giggles when tickled, but has not yet mastered the art of speech.  In addition, she has suffered several potentially deadly illnesses and conditions.  But the girl who may hold the future in her genes is not without hope.  As research into her condition continues she may not only help others, but herself as well.  Scientists have already discovered that parts of her body are aging, just at different speeds.  Those researching her case have suggested that it's likely that her genes have been damaged in such a way that it makes it difficult for her body to coordinate the rate at which her body develops.  Scientists suggest if they could only figure out which gene, they could switch it on and off at will.  And maybe switching it on in Brooke would help her develop into an adult.  Would it be possible to then stop aging for the rest of us?