Scientists are puzzled by a mysterious plume that erupted off the surface of Mars in 2012. On the right, the location of the plume is identified in the yellow circle. On the left, close-up views of the changing plume morphology in images taken by W. Jaeschke and D. Parker on March 21, 2012. The background is a region on Mars known as Terra Cimmeria, where the plume formed. (Image source NOAA).