Post by Dr. Norbert Schorghofer. Senior Scientist, Planetary Science Institute
Recurring slope lineae (RSL) are dark narrow streaks on Mars that have puzzled scientists since their discovery in 2011. Image 1 shows a 3-dimensional perspective of a landscape with some of these flow features. RSL form and grow annually and mostly in the warm season, so the mechanism by which they form and grow is tantalizing. To what extent are RSL related to temperature or water? In rugged terrain there are stark temperature contrasts between pole‐facing and equator‐facing slopes that infrared cameras on Mars-orbiting spacecraft cannot spatially resolve. New modeling capabilities make it possible to overcome this limitation and provide surface temperatures at high spatial resolution.

Image 1: An image combining orbital imagery with 3-D modeling shows RSL on a slope inside Newton Crater. Image credit: NASA/JPL-Caltech/University of Arizona.