A few weeks ago, I brought you the story that bright radar reflections from under Mars’ south polar ice caps were probably not water but more likely salty ice or some other conductive mineral.⠀ ⠀ Now, a new paper in Geophysical Research Letters, which is apparently having a banner week for newsworthy publications, provides multiple lines of evidence that show the mineral under the ice is a specific type of clay called smectite. The lead author on this paper is Planetary Science Institute’s Isaac Smith. Not only did the team use experimental work and some modeling to demonstrate their hypothesis, but they also found evidence of smectites around the edges of that polar ice cap.⠀ ⠀ Read my full story: buff.ly/3fQmbXp⠀ ⠀ IMAGE: This image taken by NASA’s Mars Reconnaissance Orbiter shows ice sheets at Mars’ south pole. The spacecraft detected clays nearby this ice; scientists have proposed such clays are the source of radar reflections that have been previously interpreted as liqui...