mercury

Recent images from the robotic MESSENGER spacecraft that flew by Mercury last October show previously uncharted regions of Mercury that have large craters with an internal smoothness similar to the maria on Earth's own Moon. Therefore, like our Moon's maria, these craters on Mercury are thought to have been flooded by lava floes that are old but not as old as the surrounding more highly cratered surface. The above image mosaic of the western limb of Mercury was created by MESSENGER as it approached the Solar System's innermost planet last October. Old and heavily textured terrain runs across much of the image bottom, while across the middle left lies comparatively smooth impact basins where small craters may appear similar at first to protruding hills. MESSENGER will buzz past Mercury again later this year before entering orbit in 2011.

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all line up

Last week, Mercury, Venus, and the Moon all appeared close together in Earth's sky. This picturesque conjunction was caught on camera behind elements of the Australia Telescope Compact Array (ATCA) near the town of Narrabri in rural New South Wales. The ATCA consists of six radio telescopes in total, each one larger than a house. Together they form one of the highest resolution measurement devices in the world. Impressive planetary conjunctions occur every few years. Involving the brightest objects in the night sky, this alignment was easy to spot just before sunrise. In the picture, taken on the morning of March 6, Mercury is the highest of the three bright celestial beacons.


Credit & Copyright: Graeme L. White & Glen Cozens