Bruce Murray Space Image LibraryMars polar vortex from MARCI Mars polar vortex from MARCI This is a MARCI color mosaic of the north polar region of Mars from 40-90 degrees North, 0-360 degrees West, generated from data taken on October 22, 2012 (Ls = 192.8), early-autumn in the northern hemisphere. The black star shape in the center is the boundary of the terminator ("polar night"). The whitish areas are water-ice clouds. The diffuse ice clouds in the north polar region are part of the north polar hood that is a steady feature at this time of the Martian year. The polar hood has an egg-shaped structure. The clouds of the hood help denote the southern boundary of the polar vortex, which extends as far south as 49 degrees latitude. NASA / JPL / MSSSThis is a polar stereographic projection (west longitude increasing in a clockwise direction from the bottom of the image).