Messenger in orbit around Mercury
Above, an annotated version of the first orbital image, showing areas of the south pole never before seen.
From the press conference about the first Messenger images from Mercury orbit:
- After more six years and five billion miles of travel, the spacecraft arrived almost exactly the predicted orbit, a highly elliptical polar orbit 12 hours long and ranging from 129 miles by 9483 miles.
- All instruments are working, as designed.
- They expect to have downloaded about 1500 images by tomorrow, out of a total of 75,000 over the year of operations.
Some of the scientific questions they hope Messenger will help them answer:
- They hope to find out if there is water-ice in the floors of the planet’s polar craters!
- Why the number and size of secondary craters on Mercury is “surprisingly large,” compared to the Moon.
- The origin of Mercury’s magnetic field.
- Why is Mercury so dense, which in turn might explain how the inner planets of the solar system came to be.
This image shows an area near Mercury’s north pole,, never seen before. Because the Sun is low on the horizon, the shadows are long, which brings out the details. That there might be water ice in Mercury’s polar craters is beyond astonishing.
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