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Evidence Of Life On Mars May Be Underground
Minerals beneath the surface of Mars could hold the strongest evidence that the planet may once have supported life, according to new research.
Half of all life on Earth consists of simple micro-organisms hidden in rocks beneath the surface. Scientists have now suggested that the same may be true of Mars.
Research published in the journal Nature Geoscience suggests the ingredients of life have been present in the "Martian subsurface" - a zone up to three miles below the ground - for much of Mars' history.
Many rocks brought up from the "Martian subsurface" contain clays and minerals whose chemical make-up has been altered by water, an essential element to support life.
Some deep craters on Mars may also have acted as basins where groundwater likely emerged to produce lakes, according to a statement released by the University of Aberdeen.
"Exploring these rocks on Mars, where the ancient geologic record is better preserved than on Earth, would be like finding a stack of pages that have been ripped out of Earth's geological history book," said Dr Joseph Michalski, lead author and planetary geologist at the Natural History Museum.
"Whether the Martian geologic record contains life or not, analysis of these types of rocks would certainly teach us a tremendous amount about early chemical processes in the solar system."
Current exploration of Mars focuses on investigating surface processes because sedimentary rocks are most likely to provide the best chance of evidence for habitability.
However, the evidence suggests that the Martian surface environment has been inhospitable to life for billions of years.
In future missions, scientists may choose to target rocks related to the surface or subsurface, or perhaps do both by targeting areas where sedimentary rocks formed from subsurface fluids.
Dr Michalski said the new research presents a "strong case for exploring the subsurface, as well as the surface", of the Red Planet.
But he added: "I don't personally think we should try to drill into the subsurface to look for ancient life.
"Instead, we can study rocks that are naturally brought to the surface by meteor impact and search in deep basins where fluids have come to the surface."