Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2014 August 19
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Contrasting Terrains on Comet Churyumov-Gerasimenko
Image Credit: ESA / Rosetta / MPS for OSIRIS Team; MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Explanation: Where should Philae land? As ESA's robotic spacecraft Rosetta circles toward Comet 67P/ Churyumov-Gerasimenko, a decision must eventually be made as to where its mechanical lander should attempt to touch-down. Reaching the comet earlier this month, Rosetta is sending back detailed pictures of the comet's unusual nucleus from which a smooth landing site will be selected. Pictured above, near the image top, the head of the comet's nucleus shows rugged grooves, while near the image bottom, the body shows a patch-work of areas sometimes separated by jagged hills. Some of the patch-work areas apparent on both the head and body seem to have fields of relatively smooth terrain. In the connecting area called the neck, however, visible across the image center, a relatively large swath of light-colored smooth terrain appears, punctuated occasionally by large boulders. Rosetta is scheduled to release Philae toward the dark mountain-sized comet nucleus with an anticipated landing date in November.

Tomorrow's picture: interstellar tornados


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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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