Mars: Scientists Find Evidence of Present-Day Water | Space Exploration

Observations from NASA’s Mars Reconnaissance Orbiter have revealed what may be seasonal flows of salty water.

Recurrent slope linea on the south-facing slope of a crater on the floor of Melas Chasma, Mars. Image credit: McEwen AS et al / NASA / JPL-Caltech / University of Arizona.

Finger-like geological features, called recurrent slope linea, were first reported in 2011 on mid-latitude southern Martian slopes. They appear and extend down rocky slopes during spring through summer, then fade in winter and return the next spring.

The new observations have tracked the seasonal changes in these recurring features on several slopes near the Martian equator.

This map shows locations of confirmed recurring slope linea on Mars. Image credit: McEwen AS et al / NASA / JPL-Caltech / University of Arizona.

“The equatorial surface region of Mars has been regarded as dry, free of liquid or frozen water, but we may need to rethink that,” said Dr Alfred McEwen from the University of Arizona in Tucson, who is the lead author of the paper published in the journal Nature Geoscience.

Five well-monitored sites with the recurrent slope linea are in Valles Marineris, the largest canyon system in the Solar System.

Recurrent slope linea on north-facing slopes in Coprates Chasma, Mars. Image credit: McEwen AS et al / NASA / JPL-Caltech / University of Arizona.

At each of these sites, the linea (typically less than 5 m wide and up to 1.2 km long) appear on both north- and south-facing walls. On the north-facing slopes, they are active during the part of the year when those slopes get the most sunshine. The counterparts on south-facing slopes start flowing when the season shifts and more sunshine hits their side.

“Although the origin of the recurring slope linea remains an open question, our observations are consistent with intermittent flow of briny water,” Dr McEwen wand his co-authors wrote in the paper.