Transit of Venus
Transits of Venus across the disk of the Sun are among the rarest of
planetary alignments. Indeed, only six such events have occurred since
the invention of the telescope (1631, 1639, 1761, 1769, 1874 and 1882).
Two transits of Venus are occuring within a few years of eachother -
the first was on June 08, 2004, the next will be June 06, 2012.
Transits of Venus are only possible during early December and early
June when Venus's orbital nodes pass across the Sun. If Venus reaches
inferior conjunction at this time, a transit will occur. Transits show
a clear pattern of recurrence at intervals of 8, 121.5, 8 and 105.5
years. The next pair of Venus transits occur over a century from now on
2117 Dec 11 and 2125 Dec 08.
More: NASA Sun-Earth - Venus Transit 2004
More: Science@NASA - James Cook and the Transit of Venus
More: Space Weather - Transit of Venus Photo Gallery

