Mars has more water than thought

By Richard Chirgwin 

It's a big day for extra-terrestrial water: not only are there hints of water on the moon, but now Carnegie says that the mantle of Mars might have water concentrations similar to those found on Earth.

Specifically, the researchers say that rocks in Mars’ mantle could have concentrations of water between 70 and 300 parts per million – which compares very favourably to Earth’s mantle, where rocks show concentrations between 50 and 300 ppm.

The scientific team, which included Francis McCubbin (formerly of Carnegie and now at the University of New Mexico), and Erik Hauri, examined meteorites that originated on Mars.

These shergottite meteorites were created by the partial melting of Mars’ mantle, and crystallised at or near the surface of the planet before being ejected about 2.5 million years ago to arrive on Earth. Analysing the water content of the mineral apatite in two meteorites with “different processing histories”, Hauri said the water content of the different samples was quite similar.

“The results suggest that water was incorporated during the formation of Mars and that the planet was able to store water in its interior during the planet’s differentiation”, he says in Carnegie’s announcement.

Hauri believes the amount of water present in the sample could be sufficient for Mars to have once sustained life – if processes such as volcanoes brought the water to the surface. ®