While Mars is now a dry and desolate planet, in the distant past it had a thick atmosphere and liquid water on the surface. Researchers from the Indian Institute of Remote Sensing and the Indian Institute of Technology, Bombay have used data gathered by the Mangalyaan mission to investigate ancient megafloods on Mars. The velocity and volume of the events have been estimated based on the beautiful data returned by ISRO's first mission to the Red Planet.

Piles of debris transported over great distances, imprints of furious waves on the ground, and eroded layers of sedimentary deposits are just some of the signs of the wet history of Mars that have been identified by spacecraft examining the Red Planet. While it is well known that Mars hosted water in the distant past, the exact time period over which the water was present, as well as when, where and why all the water disappeared are all enduring mysteries, with spacecraft from Mars continuously improving and finetuning our scientific understanding. Now, Indian researchers have used data from ISRO’s Mars Orbiter Mission (MOM) or Mangalyaan, to provide additional insights into megafloods in ancient Mars.

The researchers tracked outflow channels, or ancient flooding events that led to the reshaping of the Martian surface. The researchers focused on four regions, the Mangala, Kasei, Ravi and Ma’adim which are all networks of crisscrossing channels. All of these formations witnessed periodic flooding events, which were possibly linked to periods of intermittent volcanism. These outflow channel systems stretch for hundreds of kilometres across the surface of Mars, and consists of a violent, tortured terrain shaped by the furious passage of large amounts of water. The researchers have used modelling to estimate the quantities of water that flowed through these channels, known as ‘valles’, and their velocity.

About 3.5 billion cubic metres of water moved through Kasei Valles for example, at velocities in excess of 20 metres per second. The Kasei Valles stretches for over 2,000 kilometres across the surface of Mars, with a maximum width of 260 metres. It is the largest among the four discharge channels investigated for the study. Such studies are helpful for guiding future missions to the Red Planet, which know exactly where to go to investigate the wet history of Mars, and consequently, signs of any ancient Martian life. A paper describing the findings has been published in Current Science.