“We are still debating their origin, but they appear to have a relatively young age and may suggest a more abundant than expected volatile component in Mercury’s crust.” ![]() “The etched appearance of these landforms is unlike anything we’ve seen before on Mercury or the moon,” said Brett Denevi, a staff scientist at the Johns Hopkins University Applied Physics Laboratory and a member of the Messenger imaging team. ![]() These pits are often surrounded by diffuse halos of higher-reflectance material, and they are found associated with central peaks, peak rings and rims of craters. New targeted MDIS observations at up to 10 meters per pixel reveal these patchy deposits to be clusters of rimless, irregular pits varying in size from hundreds of meters to several kilometers. Without high-resolution images to obtain a closer look, these features remained a curiosity. The broad expanses of plains confirm that volcanism shaped much of Mercury’s crust and continued through much of Mercury’s history, despite an overall contractional stress state that tended to inhibit the extrusion of volcanic material onto the surface.Īmong the fascinating features seen in flyby images of Mercury were bright, patchy deposits on some crater floors. Messenger’s new orbital images show that the plains are likely among the largest expanses of volcanic deposits on Mercury, with thicknesses of up to several kilometers. Flyby images from Messenger and from Mariner 10 in the 1970s indicated that smooth plains may be important near the north pole, but much of the territory was viewed at unfavorable imaging conditions. ![]() Orbital images reveal broad expanses of smooth plains near Mercury’s north pole. These base maps are providing the first global look at the planet under optimal viewing conditions. Those milestones provide important context to the continuing feast of new observations that Messenger has been sending home on nearly a daily basis.”Īs part of Messenger’s global imaging campaign, the Mercury Dual Imaging System, or MDIS, is acquiring global monochrome and stereo base maps with an average resolution of 250 meters per pixel and a global color base map at an average of 1.2 kilometers per pixel. “We completed our first perihelion passage from orbit on Sunday, our first Mercury year in orbit on Monday, our first superior solar conjunction from orbit on Tuesday and our first orbit-correction maneuver on Wednesday. “Messenger passed a number of milestones just week,” said Messenger principal investigator Sean Solomon of the Carnegie Institution of Washington. And scientists now know that bursts of energetic particles in Mercury’s magnetosphere are a continuing product of the interaction of Mercury’s magnetic field with the solar wind. Maps of the planet’s topography and magnetic field are revealing new clues to Mercury’s interior dynamical processes. Measurements of the chemical composition of Mercury’s surface are providing important clues to the origin of the planet and its geological history. Tens of thousands of images of major features on the planet-previously seen only at comparatively low resolution-are now available in sharp focus. ![]() Its instruments are performing the first complete reconnaissance of the planet’s geochemistry, geophysics, geologic history, atmosphere, magnetosphere and plasma environment. The spacecraft entered orbit around Mercury on March 17, becoming the first spacecraft ever to do so. After nearly three months in orbit about Mercury, Messenger’s payload is providing a wealth of new information about the planet closest to the sun, as well as a few surprises.
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