The next transit of Venus, when the planet Venus will appear as a small, dark disk moving across the face of the Sun, will begin at 22:09 UTC on 5 June 2012, and will finish at 04:49 UTC on 6 June. Depending on the position of the observer, the exact times can vary by up to ±7 minutes.
The orbit of Venus is inclined 3.4° with respect to Earth's orbit. It intersects the ecliptic at two points or nodes that cross the Sun each year during early June and December. If Venus happens to pass through inferior conjunction at that time, a transit will occur.
In the 18th century astronomers set out to far-flung corners of the globe to time the transit of Venus. Combined, their results gave them the first accurate measurement of the distance between the Earth and the sun, a figure they calculated to be between 93 million and 97 million miles (172-180 million kilometres). Today, the accepted distance is 93 million miles. The result allowed astronomers to calculate the size of the solar system.
From Earth, Venus would be at inferior conjunction, passing directly between us and the sun. But as seen from Venus, our Earth would be at opposition to the sun and interestingly, any Venusians looking Earthward would see (assuming they were above the planet's clouds, perhaps riding in a balloon) an object far brighter than any of the neighboring stars.
Viewed from Venus, the Earth would blaze like some stupendously bright bluish-white star in the constellation of Ophiuchus, the serpent holder. Our home planet would appear to blaze at a resplendent magnitude of -6.5. That's nearly five times brighter than Venus would appear for us!
Venus is one of the brightest objects in the night sky, and its pointlike brilliance makes it a prime candidate for misidentification. According to the online Museum of Unnatural Mystery, Venus is the natural object most likely to be mistaken for an unidentified flying object, or UFO.
The transit is happening during a 6-hour, 40-minute span starting just after 6 p.m. EDT in the United States. What you can see and for how long depends on what the sun's doing in your region during that exact window, and the weather.
Those in most areas of North and Central America will see the start of the transit until the sun sets, while those in western Asia, the eastern half of Africa and most of Europe will catch the transit's end once the sun comes up.
Humans have used the transit of Venus to understand the solar system and even the universe. Although it's just a dot crossing the disk of the sun from earth's view, Edmund Halley (of the famed comet) determined that the distance from Earth to the Sun could be determined from a Venus transit.
SHI International today announced that the SHI Cloud data center will help power the first-ever webcast of the planet Venus' transit across the sun.
On average, transits of Venus happen every 80 years or so. However, this average figure is messy. You see, Venus transits occur in a 'pair of pairs' pattern that repeats every 243 years. First, two transits take place in December (around Dec 8th), 8 years apart. There follows a wait of 121.5 years, after which two June transits occur (around June 7th), again 8 years apart. After 105.5 years, the pattern repeats.
"The side of Venus facing us will appear as a small, black dot," Jones said, noting that it takes nearly 7 hours for the transit to occur. ... "Only six Venus Transits have happened since the invention of the telescope." The transits occur in pairs with more than 100 years in between each transit pair.
Attempting to view the sun directly during the transit of Venus without the right equipment can be dangerous, much like during a solar eclipse. But for those with the right tools, it will make for an awesome display.
To view the transit, NASA suggests using eclipse shades or a number 14 welder's glass. A telescope with a special type of solar filter can also be used.
Often referred to as the "Evening Star" or "Morning Star," Venus is the brightest natural object in our sky after the Sun and the Moon. As the second planet from the Sun, it's closer to the Sun than the Earth is.
A "transit" of Venus occurs when Venus passes between us and the Sun in such a way that we can see Venus's silhouette backlit by the Sun's brilliant light. It last happened in 2004, but it won't happen again until 2117.