It’s that rare, once-in-a-lifetime occasion – infact it is, since no one alive today has ever witnessed it. The last time the transit of planet Venus (between Earth and the Sun) occured was in 1882 and it will occur next in year 2012. Transits of Venus occur twice — eight years apart — about every 120 years. The last pair of transits were in 1874 and 1882 and helped astronomers calculate the distance of the Earth from the sun. The transit of Venus has happened only six times in the telescopic age — 1631, 1639, 1761, 1769, 1874 and 1882. After 2012 it is set to happen again in 2117.
Being here in Australia, I’ve come to realize another reason for the significance of this event. The transit of Venus in 1882 led to the first British exploration of the Australian east coast (Great Barrier Reef) by Captain James Cook (more). If it wasn’t for the transit of Venus, many Australians today might trace their ancestry to French origins instead of English.
Venus appearing as a small black dot on the lower edge of the Sun starting its six-hour transit.
Scientist Knud Jahnke points to Venus at the Astrophysical Institute of Potsdam, eastern Germany.