Spectacular Imagery Reveals Traces Believed to Come From Liquid Water Flowing on Today's Mars

The dark, narrow streaks flowing downhill in this crater on Mars are inferred to be formed by seasonal flow of liquid water. The streaks are roughly the length of a football field. (Source: NASA/JPL-Caltech/Univ. of Arizona) If you've paid attention to the news at all today, you've probably heard about the compelling new evidence that liquid water flows on Mars — present tense. The news has gotten a lot of coverage today. Among the best is a post by Cory Powell, my fellow blogger here at Discover. You can find his excellent summary of the science, and why it is significant, right here. I decided to dedicate my post to spectacular imagery, including the dramatic image above. You're looking at Horowitz Crater on Mars. The image is based on data from the High Resolution Imaging Science Experiment, or HiRISE camera, on NASA's Mars Reconnaissance Orbiter. Look for the dark streaks fanning out from the base of the more rugged terrain. These "recurring slope lineae" have been seen on Mars before, and scientists have suspected that they were traces left by running briny water. Now, a spectrometer on the orbiter has revealed hydrated salts on the slopes at Horowitz Crater, corroborating the hypothesis.