Less Than Zero
This elevation map of the Beethoven basin is color-coded to show the height of features on Mercury's surface. Mercury lacks a "sea level", so the zero-point reference elevation is defined to be the mean planetary radius of 2440 km. Blue areas, such as within Bello crater on the floor of Beethoven, have negative elevations. The red and white areas to the southwest are more than 8 km higher than the lowest points in this area.
Date acquired: February 27, 2012
Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington