Visible in the image above (the green lines point to it), the protuberance appears to have a high albedo and even projects a shadow on the rock below. The image was taken with the right Mastcam on Curiosity on Sol 173 — January 30, 2013 here on Earth — (see the original raw image here), and was pointed out to us by Elisabetta Bonora, an image editing enthusiast from Italy .... http://www.universetoday.com