The Moon, Sun, and Earth will treat the Lower 48 to a total lunar eclipse tonight. Most of the states will see the entire eclipse, while the West Coast will see all but a small part of the show.
A lunar eclipse occurs when the full Moon lines up directly opposite the Sun, so it passes through Earth's long shadow. The Moon's orbit around Earth is tilted a bit, so most months, the Moon just misses the shadow. But at least twice a year, the geometry is just right, so the Moon passes through the shadow, creating an eclipse.
The partial eclipse begins at 7:43 p.m. Central Time, when the Moon first touches the dark inner portion of the shadow. As the Moon moves deeper into the shadow, it looks like something is taking a bigger and bigger "bite" from its disk. In ancient times, this appearance inspired people to conjure stories of dragons or evil spirits. But there's nothing supernatural about it -- it's part of the clockwork motions of the heavens.
The Moon will be completely immersed in the shadow -- the total phase of the eclipse -- by around 9 o'clock, and it'll remain there for almost an hour. The Moon won't completely disappear, though; sunlight scattered through Earth's atmosphere will color its disk dark red or gray. The partial eclipse will end a little after 11 p.m.
The entire eclipse will be visible from the Rocky Mountains eastward. Farther west, the eclipse will just be getting underway as the Moon rises.
Script by Damond Benningfield, Copyright 2007 A faint stellar corpse -- after this.
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