Evidence of water FOUND ON MARS

Mars Express detects possible reservoir beneath Martian south pole

After decades of searching, evidence of a reservoir of liquid water has been found beneath the surface of Mars. The discovery was made by ESA’s Mars Express spacecraft, using its Mars Advanced Radar for Subsurface and Ionosphere Sounding instrument (MARSIS), the first radar sounder ever to orbit another planet.

MARSIS uses radar signals to probe the upper layers of Mars’s south polar region, allowing astronomers to piece together the structure hidden beneath. The top 1.5km appear to be made up of layers of dust and ice, but underneath this is a particularly reflective layer. Repeated measurements revealed that the body of water is at least several tens of centimetres deep and around 20km wide.

“This subsurface anomaly on Mars has radar properties matching water or water-rich sediments,” says Roberto Orosei, the principal investigator of the MARSIS experiment, who led the study. “This is just one small study area; it is an exciting prospect to think there could be more of these underground pockets of water elsewhere, yet to be discovered,” says Orosei.

Though we know that Mars used to be wet billions of years ago, this is the first time liquid water has been found on the planet as it is now. It’s thought that the water is salty; this, combined with the pressure from the rocks above, would prevent it from either evaporating away or freezing.

“This thrilling discovery is a highlight for planetary science and will contribute to our understanding of the evolution of Mars, the history of water on our neighbour planet and its habitability,” says Dmitri Titov, the project scientist for Mars Express.