Dark, fingerlike streaks on the surface of Mars that come and go with the warm and cold seasons may well be evidence of salty water.
Oblique view of Newton Crater recurring slope lineae (RSL). This image has been reprojected to show a view of the RSL-covered slope as would be seen from a helicopter inside the crater, with a synthetic Mars-like sky. NASA/JPL/University of Arizona
President Trump and first lady Melania Trump lit the National Christmas Tree for the first time. The program was hosted by television personality Kathie Lee Gifford and actor Dean Cain and featured performances by the Beach Boys, Jack Wagner, Wynonna Judd, Craig Campbell and others.