for National Geographic News
Solar eclipses have been blamed in the past for war, famine, and the deaths of kings. But the upcoming total eclipse on Friday, August 1, will mostly be celebrated by excited sky-watchers—even if it won't break any records. (See photos of recent solar eclipses.)
The sun will be completely obscured for just under two and a half minutes, "a tad on the short side," according to astrophysicist Fred Espenak, an eclipse expert based at the NASA Goddard Space Flight Center.
A typical eclipse lasts for three minutes, Espenak said, and the longest possible is seven and a half minutes.
When it starts, this year's full eclipse will be visible from a narrow arc spanning the Northern Hemisphere.
Before moving east, the eclipse will start over far-northern Canada around 8:30 a.m. Greenwich mean time (or about 4:30 a.m. eastern time). The eclipse will reach totality—when the sun is totally hidden by the moon—in just under an hour.
In a much wider swath of the globe—including northeastern North America along with most of Europe and Asia—people will be able to see a partial eclipse.
"Drop Dead Gorgeous"
The moon crosses between Earth and the sun once a month during the new moon. For an eclipse to happen, the moon has to come directly between the two bodies—it can't be too high or low relative to Earth. (See photos of the full moon from Earth and space.)
Sometimes the moon will be close enough that just an edge will pass in between, resulting in a partial eclipse.
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