June 1, 2012 — Beginning at 6:10 p.m. on Tuesday, the planet Venus will pass in front of the sun as seen from Earth. Such events, called "transits," are quite rare; this will be the last time that Venus transits the sun until Dec. 11, 2117.
To celebrate the rare occurrence, the University of Virginia's Department of Astronomy, part of the College of Arts & Sciences, will host two events: an informational lecture about Venus transits on Sunday at 3 p.m. in the Chemistry Building auditorium, and a viewing event Tuesday from 6 p.m. to sunset (weather permitting) at Darden Towe Park.
Astronomer Edward Murphy, who heads up the astronomy department's outreach programs, will give the Sunday lecture and will host the Tuesday evening viewing.
"On Tuesday we will have six to eight telescopes set up, with safe solar viewing filters, for people to watch the event near the picnic shelter," he said.
The picnic shelter is located near the dog park and the Lewis and Clark Exploratory Center (it can be seen in this Google Map of the area).
Astronomers will be on hand to explain the event and answer questions. Murphy said people can view the transit from home if they have a telescope with a proper solar filter and are familiar with its use. Otherwise, viewers risk blindness if they attempt to view the transit with the naked eye, which essentially is staring at the sun.
Historically, transits of Venus were used to determine the distance from the earth to the sun, and the scale of our solar system, Murphy said.
Transits of Venus across the sun occur in pairs. The transits in a pair are eight years apart, with the pairs themselves separated by either 105.5 or 121.5 years. The transit on Tuesday is the second in our current pair (the first was in June 2004). The last pair was in 1874 and 1882 and the next pair is in 2117 and 2125.
The transit will begin Tuesday at 6:10 p.m. Venus will appear as a small black dot shadowed against the intensely bright surface of the sun. It will take Venus six hours and 40 minutes to cross in front of the sun, but not all of the transit will be visible from Virginia because the sun will set at 8:34 p.m.