Have you ever played a game whereby you pretended the entire floor of a room is lava? In the case of this unnamed crater at Mercury's equator, it wasn't a game.

Smooth floors are often observed in impact craters on Mercury that are the result of pooled impact melt. However, this crater is far shallower, and so substantially more filled with smooth plains material, than is expected for a feature this size. The most likely explanation then is that at some point after its formation, this crater was filled with lava, similar to that seen within many other large craters across the planet. A key question MESSENGER scientists are now investigating is whether volcanic activity elsewhere produced lavas that broke through craters' walls and flooded their interiors, or if activity within craters themselves is responsible.

This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week.

Date acquired: April 28, 2011
Image Mission Elapsed Time (MET): 244751374
Image ID: 185933
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -0.39°
Center Longitude: 204.77° E
Resolution: 81 meters/pixel
Scale: The diameter of this crater is approx. 70 km (44 mi.)
Incidence Angle: 69.1°
Emission Angle: 35.1°
Phase Angle: 78.2°
(North is to the bottom of the image.)

The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. Visit the Why Mercury? section of this website to learn more about the key science questions that the MESSENGER mission is addressing. During the one-year primary mission, MDIS acquired 88,746 images and extensive other data sets. MESSENGER is now in a year-long extended mission, during which plans call for the acquisition of more than 80,000 additional images to support MESSENGER's science goals.

These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.