It's the most infrequent, predictable occurrence in the heavens, and it's happening soon.
On June 5, 2012 at 6:03 p.m. EDT, the planet Venus will cross directly between Earth and the sun—a journey completed only six times since the invention of the telescope. To spectators, the planet will appear as a black dot moving from left to right across the sun's bright disk. Among the rarest planetary alignments, the transit of Venus follows an odd cycle: Two occur eight years apart, and then 105 or 121 years pass until one happens again. After June 5, the next transit will come about in 2117. The precise moments when Venus appears and disappears from Earth's field of view are of particular significance. In the 18th century, scientists used the timing of the transit to improve early calculations of the distance between the sun and Earth. The videos below show how Venus will make its final transit of the century.
Please give credit for this item to: NASA's Goddard Space Flight Center Cover image courtesy of NASA's Transition Region and Coronal Explorer (TRACE) GOES satellite image, captured by the GOES 12 satellite, courtesy of NOAA Map of transit visibility courtesy of Michael Zeiler
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