Rare Venus Transit Will Darken Earth Tuesday

One of the rarest astronomical phenomena will occur tonight, Tuesday, June 5, when Venus will move across the face of the sun, creating solar eclipse-like conditions and darkening planet Earth for about six and a half hours.

The planet will begin its transit at around 5:30 pm, peaking from 7:00-9:00 pm and waning from 9:00-11:00.  From 11:00 pm to 1:00 am, the planet will fade into the night sky.

Because of the excitement created by this event -- this is the last Venus transit until 2117 – NASA has set up a live-streaming broadcast to watch the planetary transit.  In addition, experts from NASA's Marshall Space Flight Center and NASA's Ames Research Center will be available to answer viewers' questions from 4:30 p.m. to 1:00 a.m via a live Web chat. 

Of course, many scientists and amateur astronomers will be watching the rare event by telescope tonight.  If you plan to view it that way, the American Academy of Ophthalmology cautions that it’s just as dangerous to view the event directly as it would be to watch a solar eclipse straight-on. Sunglasses, binoculars with filters, neutral density filters, exposed photographic or radiographic film will not protect your eyes.

Watching the transit at a planetarium or at a university’s astronomy department, especially if it can be projected on a screen, may be the best way to view it.

The NASA website notes, “The transit of Venus also demonstrates how scientists on NASA's Kepler mission are detecting planets beyond our solar system. NASA's Kepler space telescope measures the change in brightness from distant stars when a planet passes or transits in front of the star. From the transit data, scientists can determine the size of the planet, the length of its year and calculate the distance the planet is from its star. Kepler has confirmed 61 planets and more than 2,300 planet candidates using the transit method.”

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