NOTE: We are working on lesson plans to help integrate these materials into the classroom, so check back often!
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 in this tutorial (25MB)] [Browsers Supported]
If the QuickMap is not loading properly or you want a larger version [click HERE]
MESSENGER Data at your Fingertips
Below are several layers of data collected over time for Mercury from various sources and instruments including 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 stacked on top of one another in various arrangements 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.
- Two tools that might help you get your bearings on Mercury’s north polar region are: north pole coordinate grid, crater names.
Watch & Learn
- As you know by now, discovering water-ice on Mercury did not happen overnight! Let MESSENGER science team member Nancy Chabot and engineering team member Alice Berman help teach you about the long scientific process that has led to this dramatic conclusion. This video captures their presentation for a teacher workshop in which scientists and engineers talked about the challenges (and great benefits) of space exploration. [Watch it HERE]
- Do you want more of the science behind this discovery? Watch the NASA Press Conference where MESSENGER scientists share their data in support of water-ice on Mercury. [Watch the Press Conference] [Supporting images, graphics, and videos]
- One of the reasons water-ice remains stable on the planet closest to the Sun is the fact that Mercury’s spin axis is not tilted like Earth’s. Mercury’s spin axis is nearly vertical so very little sunlight reaches the poles. Moving away from the poles, small changes in the topography, such as crater walls, create areas of permanent shadow. Watch this animation depicting the illumination of the topography near Mercury’s north pole, showing the small proportion of sunlight that reaches Prokofiev crater’s floor and rim. How do the shapes of the shadows change as the craters are further from the Sun? [Watch the video and learn more HERE]