NASA Messenger MDIS Image: Mercury's Caloris basin in sharp relief - Video

Mercury’s uneven surface comes into sharp relief when the sun sits low on the planet’s eastern horizon. 

The relatively smooth floor of the Caloris basin lies on the right, with the rim and exterior of the basin to the left. 

The knobby texture outside of the basin may have arisen due to blocks of material ejected by the basin-forming impact. 

MESSENGER spacecraft acquired this image as part of the Mercury Dual Imaging System (MDIS) high-incidence-angle base map. 

High incidence angles, obtained when the sun sits near the horizon, create long shadows that accentuate the small-scale topography of geologic features, as seen here.

This animation shows 89 wide-angle camera (WAC) images of Mercury’s south polar region acquired by the Mercury Dual Imaging System (MDIS) over one complete Mercury solar day (176 Earth days).

This dataset enabled the illumination conditions at Mercury’s south polar region to be quantified, producing the map seen at the end of the movie and provided as a separate image.

The map is coloured on the basis of the percentage of time that a given area is sunlit; areas appearing black in the map are regions of permanent shadow.

The movie and illumination map are shown in polar stereographic projection, extending northward to 73° S, and 0° longitude is at the top. The large crater near Mercury’s south pole, Chao Meng-Fu, has a diameter of 180 km.