Mars had an extensive “northern ocean” at some point in the past, a groundbreaking analysis of the Red Planet’s gravitational field has suggested.
The work was undertaken by geophysicist Professor Gunther Kletetschka of the University of Alaska Fairbanks and the Czech Republic’s Charles University and his colleagues.
It combined gravity measurements with topographic data on the Red Planet collected by NASA’s Mars Global Surveyor between November 1996 and January 2001 to map out an average ancient shoreline on Mars.
According to the team’s new map, water may have flowed into the “paleoocean” via the Valles Marineris — vast canyons on Mars’ surface that are surpassed in length in the Solar System only by the mid-ocean ridge system of Earth.
Kletetschka said: “A lot of people are excited about water on Mars because there may be life forms that once existed on Mars, or maybe exist today in some bacterial form.”
Conventional gravity analyses tend to focus on so-called “gravitational anomalies” — areas where the gravitational force is greater or weaker than average as a result of features of the planet’s surface.
Mountains, for example, cause gravity anomalies because they represent areas on a planet where there are higher concentrations of mass.
In contrast, ocean basins and trenches cause gravitational anomalies because they have lower concentrations of mass than other areas of planetary surface.
The new study, meanwhile, used “gravity aspects” — mathematical products that characterize the anomalies — which the team say can “provide complete information with a better insight [into] the celestial body”.
Kletetschka explained: “We can use this gravity approach to look for water on Mars, because we have done it already on Earth.
“In an area of northern Africa, for example, this gravity approach found a shoreline of a long-gone lake.
“Its finding was consistent with the archaeological evidence indicating a shoreline of that lake.”
The team’s past research has also suggested that an ancient lake once existed where today lies part of the Great Egyptian Sand Sea — a region of the Sahara between western Egypt and eastern Libya.
The full findings of the study were published in the journal Icarus.
The gravity aspects technique has also been used to compare geographic features on Earth with those of our other planetary next-door neighbor — the cloud-shrouded planet Venus.
The results of that study were described in a paper published in the journal Scientific Reports back in July this year.
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