Global Topographic Map of Mercury


Just in time for yesterday’s transit of innermost planet Mercury across the face of the sun, NASA released the first global elevation model of the sun scorched world, courtesy of the MESSENGER spacecraft. While Mercury is hardly at the top of anyone’s list of habitable planets, it is at least worth recalling that among its other discoveries, in 2012 MESSENGER confirmed the presence of water ice in permanently shadowed areas in craters at Mercury’s north pole .


NASA’s MESSENGER mission has unveiled the first global digital elevation model (DEM) of Mercury, revealing in stunning detail the topography across the entire innermost planet and paving the way for scientists to fully characterize Mercury’s geologic history.

The global topographic model is among three new products from the Planetary Data System (PDS), a NASA-funded organization that archives and distributes all of NASA’s planetary mission data to the public. With this 15th and last major data release, the MESSENGER mission has shared more than 10 terabytes of Mercury science data, including nearly 300,000 images, millions of spectra, and numerous map products, along with interactive tools that allow the public to explore those data.

“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, a software engineer at The Johns Hopkins University Applied Physics Laboratory (APL), in Laurel, Maryland. For the last nine years, Ensor has managed the MESSENGER Science Operations Center, which oversees the collection of data.

The First Global Topography of the Innermost Planet

The new global model complements an older product released by MESSENGER, the topography map derived from earlier measurements by the Mercury Laser Altimeter (MLA). Because of the spacecraft’s highly eccentric orbit, the MLA was able to make primary measurements only in Mercury’s northern hemisphere and near-equatorial region, leaving the topography of most of the southern hemisphere largely unknown, until now.



This new model reveals a variety of interesting topographic features, as shown in the animation above, including the highest and lowest points on the planet. The highest elevation on Mercury is at 2.78 miles (4.48 kilometers) above Mercury’s average elevation, located just south of the equator in some of Mercury’s oldest terrain. The lowest elevation, at 3.34 miles (5.38 kilometers) below Mercury’s average, is found on the floor of Rachmaninoff basin, an intriguing double-ring impact basin suspected to host some of the most recent volcanic deposits on the planet.

More than 100,000 images were used to create the new model. 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.

The full story is here.


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