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Transit of Venus
The solar system's second planet paced across the face of the sun while millions around the globe watched. The rare event named the "Transit of Venus" happens usually only once in a lifetime, and once helped early astronomers map the distance between the Earth and sun. (Kevin Frayer/AP Photo)

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Year in Review 2012: Astronomical Wonders

December 5, 2013

Once-in-a-lifetime astronomical events and monumental scientific achievements drove people to look to the skies and online on Yahoo! throughout 2012.