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Solar Eclipse: When Day Becomes Night

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The total solar eclipse of March 29, 2006 was photographed from the Space Station. The point of view, reported by National Geographic News on the day, shows how the moon passing directly in front of the sun throws its shadow on the Earth. Observers in the umbra, the dark middle of the shadow, experience a brief night.

Image courtesy NASA

But not everyone waits for a solar eclipse to come to them. The total eclipse that will be observed in parts of the Northern Hemisphere this week (August 1) is another opportunity for people who specialize in traveling to obscure parts of the globe to experience them.

Jay Pasachoff, an astronomer who has observed nearly four dozen solar eclipses in person, is one of them.

Pasachoff has received funding for decades from the National Geographic Society to study the corona, or atmosphere of the sun.

The sun is so brilliant that it is impossible to see the corona from Earth as clearly as during a total eclipse, when the moon covers the sun’s surface precisely. The scientist waits patiently for each solar eclipse then tries to position himself to view it clearly, wherever on Earth that may be. He’s even watched an eclipse from an aircraft trying to keep up with the moon’s moving shadow.

“We are incredibly lucky on Earth to have the celestial coincidence that the sun and moon appear to be the same size in the sky,” Pasachoff told National Geographic News a few years ago, when he was on his way to observe an eclipse in Africa. “Actually, the sun is 400 times bigger than the moon, but it is also 400 times farther away. Nowhere else in the solar system would we be able to see such beautiful solar eclipses.”



















Jay Pasachoff in 2005 standing in front of the largest telescope in the world, in the Canary Islands.

Image courtesy Jay M. Pasachoff

For this week’s eclipse, ‘We are basically studying how the sun shines–in particular, why and how the corona gives off the light that it does, and how it is heated to millions of degrees to do so,” Pasachoff told me. He will be observing it from Russia.

Read an interview with Pasachoff published by National Geographic News this week.

In earlier times, when a total eclipse would have been an unheard of phenomenon, it must have been bewildering if not frightening to see the sun darken and the stars come out for a few minutes in the middle of the day. Some scientists recently said that Homer was describing a total solar eclipse when he wrote in The Odyssey: “The sun has perished out of heaven, and an evil mist has overspread the world.”

Today not only do we know about eclipses and when and where they’re going to happen, we are also able to watch them as they happen, on the Internet, thanks to a live NASA video feed.

Until then, you can watch the National Geographic News video preview of the August 1, 2008 solar eclipse.

Related solar eclipse story in the news: