NASA releases first global topographic model of Mercury

090516 mercurymap 1 scaled
Mercury’s northern volcanic plains shown here in enhanced colour to emphasize different types of rocks on the surface. In the bottom right portion of the image, the 291-kilometre-diameter Mendelssohn impact basin appears to have been once nearly filled with lava. Toward the bottom left portion of the image, large wrinkle ridges, formed during lava cooling, are visible. Also in this region, the circular rims of impact craters buried by the lava can be identified. Near the top of the image, the bright orange region shows the location of a volcanic vent. – NASA/JHUAPL/Carnegie Institution of Washington

NASA has released a global digital elevation model of the Solar System’s smallest planet. The model shows stunning detail of Mercury, bringing us closer to understanding its geological history.

The model relies on data from the space agency’s MESSENGER mission. More than 100,000 images were used to create it. 

“The wealth of these data, greatly enhanced by the extension of MESSENGER’s primary one-year mission to more than four years, has already enabled and will continue to enable exciting scientific discoveries about Mercury for decades to come,” said Susan Ensor, from the Johns Hopkins University Applied Physics Laboratory.

This new model reveals a variety of interesting topographic features including the highest and lowest points on the planet.

The highest elevation on Mercury is 4.48 kilometres above the planet’s average elevation, located just south of the equator in some of Mercury’s oldest terrain. The lowest is 5.38 kilometres below average, on the floor of Rachmaninoff basin – suspected to host some of the most recent volcanic deposits on the planet.

During the orbital phase of the MESSENGER mission, images were acquired with a large range of viewing geometries and illumination conditions, which enabled the topography across Mercury’s surface to be determined.

This new map provides an unprecedented view of the region near Mercury’s north pole, which gives new insights into the volcanic activity there. At some point in the planet’s history, this region was covered by extensive lava flows more than 1,500 metres deep.

The region has been hard to observe, however, because, being close to the pole the Sun is always low on the horizon, casting many long shadows that can obscure the colours of the rocks.

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