For the first time since 2004, the east coast of the US will see a lunar eclipse. And what an eclipse it will be -- weather permitting, of course.
A lunar eclipse always happens on the night of a full moon, and is caused when the moon is on the opposite side of the Earth from the Sun and passes through the Earth's shadow. An eclipse doesn't happen every full moon because the moon's orbit is slightly tilted with respect to the Earth and the Sun, so most months the moon manages to miss the Earth's shadow.
It's moderately easy to predict lunar eclipses with nothing more than your fists. Lunar eclipses can happen at intervals of 6, 12, or 18 full moons (on rare occasions a lunar eclipse happens on the 17th month) since the last eclipse. As William Calvin pointed out in his book "How the Shaman Stole the Moon", all you have to do is use your opened palm to count "one", then fold your fingers down for "two", "three", "four" and "five". By the time you've reached six, you've got a fist, and it's that full moon you have to look out for. It doesn't work every time, but it works enough to give a shaman a terrific edge over the competition.
For people on the east coast of North America, especially around the New York area, this lunar eclipse is far from run-of-the-mill. This time, the moon will rise almost perfectly in the middle of the eclipse, so deep into the earth's shadow that it might literally be invisible.
To see this eclipse, go anyplace where you've got a clear, flat horizon to the East. Beaches and tall buildings would seem to work best. And as always, if the sky is overcast you're not going to see much of the eclipse.
All times are given for New York:
- 5:43 pm - The Moon is fully eclipsed, completely within the Earth's shadow. For most of the Northeast, the Moon will rise about this time. Depending on the state of the Earth's atmosphere, the Moon might appear to be deep red, it might appear to be deep blue (like the 1992 eclipse), it might even be so black as to be invisible. Look for where your shadow touches the horizon at sunset -- that's just about where the moon will rise.
- 6:58 pm - The Moon starts to emerge from the deepest part of the Earth's shadow. If the Moon was red when it rose, it'll start to turn yellow-orange. If it was blue or invisible, it'll start to turn red. At this point, the part of the Moon that is still dark is in the earth's shadow -- the brighter part of the Moon is being illuminated by the sunrise shining through the earth's atmosphere in places like Austraila and East Asia.
- 8:11 pm - The Moon comes totally out of the deepest part of the Earth's shadow -- it is now completely illuminated by the reddish-orange sunlight filtering through the thickest part of the Earth's atmosphere.
- 9:25 pm - The Moon comes totally out of the Earth's atmospheric shadow, and appears to be a bright white full moon. The eclipse is over.
We're space science enthusiasts at Worldchanging. For sure, studying the solar system and beyond can lead to knowledge with the potential for a big impact on problems facing us here ... but mostly, because space is cool. If you haven't watched the skies much before, this eclipse is a spectacular event to start with.
