A rare event will take place today, something that won’t happen again this century: Venus will cross over the face of the Sun.
After Tuesday evening we sink into history’s pages, having witnessed a rare astronomical event: the Transit of Venus across the sun. This won’t repeat for 105 years.
Look to the west Tuesday evening, June 5, Venus begins to cross the sun at 6:04 p.m. EDT Tuesday evening, as a notch in the sun. By 6:22 p.m., from our perspective, Venus becomes a black dot moving across the solar disc.
On this transit, it’s a 6-hour, 40-minute trek for our neighboring, interior planet – and because the sun sets – we only see a few hours of this cosmic memory.
Venus transits occur in pairs, eight years apart, alternating between 105.5 years and 121.5 years apart. Tuesday’s transit is paired with the crossing that last occurred in June, 2004.
Here are the several preceding (and present) pairings, as documented by astronomer Roy Bishop, in the Observer’s Handbook 2012:
* 1631/1639 (each in December)
* 1761/1769 (June);
* 1874/1882 (December);
* none in the 20th century;
* 2004/2012 (June).
Looking ahead, the next pair won’t occur until Dec. 11, 2117 and Dec. 8, 2125.
For many cities in the eastern U.S., including Washington, the transit starts at 6:04 p.m. on Tuesday. The central and western time zones can see more of the transit, while Hawaii can see the whole event.
Don’t look at it with your bare eyes or you might burn your optic nerve. You can watch it here.
I would add that when this happened in 1769, Captain James Cook was sent from England to the Western Hemisphere to study this event. That voyage led to the “discovery” of Australia. Capt. Cook would go on to “discover” Hawaii and Alaska. (The quotation marks mean that I know that human beings already lived in these places, but Capt. Cook was the first European to find them and to open them up for colonization.)