NASA has released this beautiful close up of the rim of a Martian impact crater, taken by the HiRISE camera aboard the Mars Reconnaissance Orbiter. The photo shows a couple of dark patches running down the slope of the crater. These are known as lineae (from the Latin for “line”) and are thought to be caused by water or some other material flowing as ice melts during the warm seasons. These particular lineae are interesting because they last longer than usual (several Martian years), so NASA is keeping a close watch on them to see what’s going on.
Normally lineae last for much shorter times. The following animation (also from HiRISE) shows lineae flowing over the course of a little more than one Martian year:
Studying lineae could provide important clues about liquid water on Mars today. There isn’t any permanent liquid water on the Marian surface today, but there was lots of water there in the distant past. Further studies of lineae could reveal exactly what causes them, and if that turns out be water (rather than sand or some other material) then that will confirm that there is still liquid water on the surface at least some of the time. That would be very interesting when it comes to the search for life.
Featured image credit: NASA/JPL-Caltech/University of Arizona