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For Teachers

MESSENGER Water-Ice Data Exploration

Despite the fact that Mercury is the closest planet to our Sun, it has long been postulated that water ice could be stable in cold, permanently shadowed regions of the north and south poles. About 20 years ago, Earth-based observations of Mercury revealed bright spots in radar data, which we call "radar-bright regions". When these data were compared with images from the Mariner 10 spacecraft, which flew by Mercury in the mid-1970’s, the radar-bright deposits were observed to be within impact craters. Yet, until the MESSENGER spacecraft began its comprehensive campaign to figure out exactly what these polar deposits might be, the question of their composition remained unanswered. Now it is your turn to mimic the scientific process, in which data from various instruments have helped to answer one of the questions guiding this mission: What are the unusual materials at Mercury’s poles?

QuickMap of Mercury’s north polar region:

Do you find it hard to believe water could remain frozen on the planet closest to our Sun? In this map tool you can explore real data by turning on and off various layers, adjusting the opacity of the layers, and zooming in closer to Mercury’s surface. [See how it works HERE!*insert screencast tutorial link*]


NOTE: We are working on new and exciting things for this activity, so check back often!

Below are several data sets collected over time for Mercury, from the Arecibo Observatory in Puerto Rico ("radar-bright" data), Mariner 10 fly-by data, and MESSENGER orbital data. You can print the indidvidual data layers on transparency paper (NOTE: choose "fit to page" when printing!). Once printed, these transparencies can be layered to show how the story of water-ice on Mercury unfolded in small chapters over decades.

  • The Mariner 10 spacecraft flew by Mercury 3 times in 1974 and 1975, capturing these images of the north polar region: Mariner 10 flyby images.
  • Radio astronomers from the Arecibo Observatory captured this Earth-based data revealing Mercury has radar-bright materials at its poles. These materials have radar characteristics that are best matched elsewhere in the solar system by water ice: radar-bright materials shown in red, radar-bright materials shown in black. (NOTE: depending on the order in which you layer the data, one color might stand out better than the other.)
  • During the 6.5 year journey from Earth to orbit about Mercury, the MESSENGER spacecraft flew past Mercury 3 times. During these flybys the spacecraft was near the equator, so only some of the north polar region was photographed: Mariner 10 and MESSENGER flyby images.
  • On March 18, 2011, MESSENGER became the first spacecraft to orbit Mercury! With that remarkable feat came mountains of data, including imaging coverage of 100% of the planet: MESSENGER orbital images.
  • Along with spectacular images of Mercury, MESSENGER collects data from several other instruments, including the Mercury Laser Altimeter (MLA). The MLA instrument maps the surface of Mercury, producing a topographic map: MLA topography data.
  • The Mercury Laser Altimeter also measures the reflectance of the planet’s surface materials. Red areas in the reflectance data indicate areas where materials are 2-3 times more reflective (or brighter) than the background surface of Mercury: MLA reflectance data.
  • Two tools that might help you get your bearings on Mercury’s north polar region are: north pole coordinate grid, crater names.