Venus to appear in once-in-a-lifetime event:
ScienceDaily (May 1, 2012) — On 5 and 6 June this year, millions of people around the world will be able to see Venus pass across the face of the Sun in what will be a once-in-a-lifetime experience.
It will take Venus about six hours to complete its transit, appearing as a small black dot on the Sun's surface, in an event that will not happen again until 2117.
In this month's Physics World, Jay M Pasachoff, an astronomer at Williams College, Massachusetts, explores the science behind Venus's transit and gives an account of its fascinating history.
Transits of Venus occur only on the very rare occasions when Venus and Earth are in a line with the Sun. At other times Venus passes below or above the Sun because the two orbits are at a slight angle to each other. Transits occur in pairs separated by eight years, with the gap between pairs of transits alternating between 105.5 and 121.5 years -- the last transit was in 2004.
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