several lunar events combined to create a once-in-a-few-decades sight in the sky.
In the northern hemisphere, this marks an end to the long days of
summer and the beginning of winter’s endless dark nights. For the other
half of the planet, Wednesday is the vernal equinox, signaling the
beginning of spring. Even though the equinox happens twice a year, every year, there are a lot of misconceptions about this seasonal transition.
First, there was a full moon. Second, it was a special type known as a harvest moon, since it was the closest full moon to the autumn equinox.
Third, the moon was as close to Earth as it will get all year, making
it a supermoon. Fourth, there was a total lunar eclipse, in which the
Earth's shadow first tints the moon red (hence the name blood moon),
then hides it entirely. (
During a total lunar eclipse, the moon falls into Earth's shadow. Here, pictures show the stages of a 2010 total eclipse..)
During a total lunar eclipse, the moon falls into Earth's shadow. Here, pictures show the stages of a 2010 total eclipse..)
On the evening of September 27, three separate lunar events converge.
The total eclipse coincides with the full moon nearest the fall
equinox, known as the harvest moon. What's more, the moon is at its
closest approach to Earth for the year, making it also a supermoon or
perigee moon. That’s why it's being coined by some as a Super Harvest
Blood Moon—a mouthful to be sure.
This confluence has happened only five times since 1900. According to NASA, the last time we saw this celestial triple combination was in 1982, and it won’t repeat until 2033.
The most spectacular part of the eclipse will be the totality phase,
when Earth's shadow completely covers the moon and turns it an eerie
red. The moon will dip into the deepest and darkest part of Earth’s
shadow, or umbra, during the totality phase, which lasts as long as 72
minutes.
This weekend's blood moon will be the last in a series of four lunar
eclipses, dubbed a tetrad, over the last two years. That pattern won’t
repeat for another 20 years or so.
This kind of overlap has only happened
five times since 1900. The last was in 1982, and the next will be in
2033. But if you missed it, fear not. We've collected the best photos of
the celestial Voltron from our Your .
What's the Autumn Equinox?
Winter is officially coming. We blew by the
longest day of the year with June’s summer solstice, and are coming up
on the autumnal equinox on Wednesday—the day when the sun passes
directly over Earth’s equator.
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