Mars, the closest candidate we have to be a potential home in the future, once had life-supporting water. However, over billions of years of evolution, the water was lost and there are no traces of it on the surface today. However, chemical and spectral analysis have established that there were once flowing rivers and lakes on the Red Planet.
The European Space Agency (ESA) has now moved a step closer and released the first water map of Mars, showing possible locations where humans could land in the future. The maps show in detail the mineral deposits across the planet jotted down over the last decade of research and observations.
Before humans set foot on Mars, the map could help identify possible locations suited for missions that could provide optimum scientific value as well.
FINDING WATER
Europe’s Mars Express Observatory and America’s Mars Reconnaissance Orbiter worked together to identify these locations that have abundances of aqueous minerals. These minerals are made from rocks that have been chemically altered by water in the past and over time changed into clay and salts.
While scientists had identified thousands of such mineral locations in a few parts of the planet, observations that spanned over the last decade have revealed hundreds of thousands of such areas in the oldest parts of the planet as well. “This work has now established that when you are studying the ancient terrains in detail, not seeing these minerals is actually the oddity,” John Carter, Institut d’Astrophysique Spatiale (IAS) said in a statement.
Finding aqueous minerals throughout the planet establishes that water was not limited to just a few locations on Mars, instead, it played a huge role in shaping the geology all around the planet. Geologists are now pondering over the question of whether water was persistent or confined to shorter, more intense episodes.
FROM WATER TO CLAY TO MINERALS
John Carter explains that scientists initially thought that only a few types of clay minerals on Mars were created when it was wet. However, the new map indicates something else. He says that while many of the Martian salts probably did form later than the clays, the map shows many exceptions where there is intimate mixing of salts and clays and some salts that are presumed to be older than some clays.
“The evolution from lots of water to no water is not as clear cut as we thought, the water didn’t just stop overnight. We see a huge diversity of geological contexts, so that no one process or simple timeline can explain the evolution of the mineralogy of Mars. That’s the first result of our study. The second is that if you exclude life processes on Earth, Mars exhibits a diversity of mineralogy in geological settings just as Earth does,” he added in the statement released by ESA.
Geologists used data from the Omega instrument on Mars Express and the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on MRO to survey the planet. While Omega provides global coverage of Mars at higher spectral resolution and with a better signal-to-noise ratio, Crism provided high-resolution spectral imaging of the surface (down to 15 m/pixel) for highly localised patches of Mars.
