Animation of Venus Crossing the Sun, from NASA
June 7, 2004 -- Tuesday morning, weather permitting, Americans east of the Rockies will be able to look up in the sky and see something that hasn't occurred since 1882. Skywatchers will see a black dot moving from left to right across the lower portion of the sun as Venus passes directly between the Earth and our star.
Called the "transit of Venus," the journey takes about six hours. Observers in Europe, Asia and the Middle East will be able to see the entire journey. But for those on the East Coast of North America, the black silhouette of Venus will be viewable for only about two hours after sunrise.
Experts warn never to look directly at the sun, but observers can use either a special type of thin plastic called a solar filter, such as a No. 13 or No. 14 welder's glass, or "eclipse glasses," which block out the sun's harmful rays. Smoked glass, stacked sunglasses, metallized candy wrappers and compact discs are not safe and may project or allow enough infrared radiation through to damage eyes.
The transit of Venus is a rare astronomical event -- and one of historic importance. Astronomers first figured out how to measure the distance of the Earth from the sun by timing Venus as it crossed the face of the sun. And the push to make measurements of the transit all over the world led to the European settlement of distant lands, including Australia.
http://www.npr.org/features/feature.php?wfId=1943177
June 7, 2004 -- Tuesday morning, weather permitting, Americans east of the Rockies will be able to look up in the sky and see something that hasn't occurred since 1882. Skywatchers will see a black dot moving from left to right across the lower portion of the sun as Venus passes directly between the Earth and our star.
Called the "transit of Venus," the journey takes about six hours. Observers in Europe, Asia and the Middle East will be able to see the entire journey. But for those on the East Coast of North America, the black silhouette of Venus will be viewable for only about two hours after sunrise.
Experts warn never to look directly at the sun, but observers can use either a special type of thin plastic called a solar filter, such as a No. 13 or No. 14 welder's glass, or "eclipse glasses," which block out the sun's harmful rays. Smoked glass, stacked sunglasses, metallized candy wrappers and compact discs are not safe and may project or allow enough infrared radiation through to damage eyes.
The transit of Venus is a rare astronomical event -- and one of historic importance. Astronomers first figured out how to measure the distance of the Earth from the sun by timing Venus as it crossed the face of the sun. And the push to make measurements of the transit all over the world led to the European settlement of distant lands, including Australia.
http://www.npr.org/features/feature.php?wfId=1943177
