Until now, it was believed that liquid water disappeared from the surface about three billion years ago.
Was there ever water on Mars?
It’s no secret that in the distant past, liquid water existed on the surface of Mars: a whole network of rivers and streams that carried Martian waters to lakes, seas, and oceans. Evidence of this are, among other things, the features of the landscape of the Red Planet, which have clear traces of water erosion.
However, unlike the Earth, Mars does not have any powerful magnetic field. As a result, the Martian atmosphere, not being protected from the action of the solar wind, thinned over time. And along with it, the Martian hydrosphere also disappeared, partly volatilizing into outer space, and partly turning into ice deposits due to global cooling and a drop in atmospheric pressure.
When did the water disappear?
Until recently, it was believed that the disappearance of liquid water from the surface of Mars ended about 3 – 3.5 billion years ago, giving the Red Planet its usual appearance.
However, the new study allows us to confidently assert that liquid water has existed on the planet for much longer than earlier estimates suggested. This study is based on data obtained by the Mars Reconnaissance Orbiter, which is still operating in the vicinity of our solar system neighbor.
Scientists analyzed previously obtained data of various types on the southern hemisphere of Mars and its landscape. This region is filled with craters as well as traces of salt deposits.
An estimate of the number of craters per surface unit made it possible to fairly accurately date the time of the occurrence of deposits (the fewer craters in the area, the younger it is). And, judging by the results of the analysis, liquid water on Mars existed “only” 2 – 2.5 billion years ago, which is a billion years “closer” to our time than previous estimates.
It is also reported that the studied salt deposits represent the first material evidence confirming the presence of liquid water on Mars in the past. Prior to this, the main evidence was considered to be those elements of the Martian landscape that, in their form, resemble the beds of dried-up rivers on Earth.
This study was made possible thanks to the unique equipment that the orbiter is equipped with: the CRISM spectrometer, as well as two cameras, including the HiRISE high-resolution color camera.
“What is amazing is that after more than a decade of providing high-resolution images, stereo, and infrared data, MRO has driven new discoveries about the nature and timing of these river-connected ancient salt ponds,” said Ehlmann, CRISM’s deputy principal investigator.
The significance of this discovery cannot be overestimated, since water is the basis of life. Therefore, the “extra” billion years of the presence of water on Mars is an “extra” billion years for the evolution of life forms that may have arisen there at one time. In any case, this discovery inspires us to explore our neighbor in the solar system in more detail, looking for traces of former, and possibly current life.
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Sources:
• Dorminey, B. (2022, January 28). NASA says Mars water likely flowed a billion years longer than previously thought. Forbes.
• Greicius, T. (2022, January 26). NASA’s MRO finds water flowed on Mars longer than previously thought. NASA.
• Hewson, G. (2022, January 27). Scientists say new evidence suggests water exists on Mars, with possibility of life. ABC News.
• Howell, E. (2022, January 27). Water on Mars may have flowed for a billion years longer than thought. Space.com.
• Leask, E. K., & Ehlmann, B. L. (2022, January 7). Evidence for deposition of chloride on Mars from small‐volume surface water events into the late hesperian‐early amazonian. AGU Journals.
• Rabie, P. (2022, January 27). NASA finds startling new evidence for recent water flow on Mars. Inverse.
