The once in 122 year event to amaze earthlings

The transit of Venus across the sun will tie stargazers to hundreds of years of history in the wee morning hours. A rare astronomical phenomenon last seen 122 years ago will be the focus of astronomers, serious and amateur, Tuesday.

"It's one of the rarest and most interesting events that astronomers can look forward to," Peter Jedicke, honorary local president of the Royal Astronomical Society of Canada, said yesterday.

A transit is when one astronomical object passes in front of another, such as an eclipse, Jedicke said.

Starting at 12:19 a.m., Venus will start to move across the face of the sun, a journey that takes six hours and creates a mini-eclipse, informs canoe.ca

According to charlotte.com people in the right places on Earth -- including the Carolinas -- will be able to see Venus move across the sun in a kind of mini-eclipse that is visible twice every century or so.

Observers lucky enough to view the entire transit will see Venus as a small black spot crossing the southern hemisphere of the sun from left to right. The planet, entering the disc of the sun at the 8 o'clock position, will take six hours to cross before exiting at the 5 o'clock position.

The last such occurrence, called a transit of Venus, was in 1882. It inspired an international effort to use the event to answer one of the most pressing scientific questions of the day: What is the exact distance between the sun and Earth?

No one alive today saw the last transit, he said, and seeing the next two will be the only chance most people have.

"These are truly once-in-a-lifetime events," Dick said. "Although the scientific importance has diminished, I think there will be a lot of interest this time among the public, based on e-mail I've seen from around the world."

The story gains momentum in the 16th and early 17th centuries, when Copernicus and Kepler discovered the true nature of planetary orbits, and it became clear that the two innermost planets must occasionally pass in front of the sun. (Speedy Mercury does it more than a dozen times per century, far more often than Venus.) The most compelling tales come from the 1761 and 1769 transits of Venus. By now astronomers had learned how to use data from transit observations to calculate the distance to the sun and the distance to the planets, and expeditions were sent to the far corners of the globe to record these events with as much precision as possible.

James Cook (later a captain but at that time still a lieutenant in the Royal Navy) sailed to Tahiti in command of the British expedition to the 1769 transit. He hoped to avoid the problems encountered by countryman Samuel Wallis on an earlier voyage: The Tahitians were fond of iron, Wallis found, and his crew happily traded the ship's nails for sexual favours with Tahitian women, until their vessel was in danger of falling apart, reports theglobeandmail.com