Odds are you don’t have any plans for 4:09 a.m. E.T. on Tuesday, Nov. 8. Assuming your calendar is indeed clear, it might be worth setting your alarm for that time, because it’s then that the last total lunar eclipse until 2025 will begin—and the show should be a dazzler.
A lunar eclipse occurs when the Earth passes directly between the sun and the moon, casting a deep shadow across the lunar surface. In theory, a lunar eclipse should happen monthly, since the moon and the sun are on opposite sides of the Earth once every 27 days during the lunar passage around the planet. But the moon’s orbit is inclined 5 degrees relative to the Earth’s equator, meaning that most of the time, the Earth’s shadow passes above or below the moon.
It is only about once every year and a half that the three bodies line up perfectly to make an eclipse happen. That year and a half frequency is just an average, however. Tomorrow’s total eclipse will actually be the second one of 2022—the last one having occurred on May 15. After this coming eclipse, a three-year wait for the next one will begin.
Where and When To Watch the Eclipse
As NASA reports, the eclipse will be visible throughout North America, Central America, Asia, Australia, and the Pacific islands. People in portions of South America—Colombia, western Venezuela, and Peru—will also be able to observe the spectacle. Shut out of the show will be Africa, most of Europe, and the Middle East.
The eclipse will unfold slowly, with the 4:09 a.m. time marking the moment the Earth’s shadow will take its first bite out of the moon. That darkness will advance slowly until, at 5:16 a.m. E.T., it will reach totality, which will last until 6:42 a.m. The moon will then sail on, with more and more of its face slowly emerging from the Earth’s shadow.
Read more: Here’s Why the Full Moon Is Sometimes Red
The moon will not completely vanish from the sky the way the disk of the sun does during a solar eclipse. Rather, it will glow a ghostly red, known colloquially as a “blood moon.” The phenomenon is a result of the sun’s light streaming through the Earth’s atmosphere, which scatters down—and filters out—blue wavelengths. Red light, however, passes straight through our planet’s air and bathes the moon throughout the duration of the eclipse. The more haze that there is in the atmosphere—caused by anything from dust storms to wildfires to volcanic eruptions—the redder the light that streams through.
An Enduring Fascination
Humanity’s fascination with lunar eclipses is a long and deep one. Astronomers can both forecast future eclipses and back-date the positions of the Earth, sun, and moon to determine precisely when they have occurred in the past. The earliest lunar eclipse to which NASA has assigned a date occurred on Feb. 6, 746 BCE, and was recorded in Babylonian records.
No matter when an eclipse happened, they were treated with both superstitions and fear.
“The Sun will turn to darkness, and the Moon to blood before the great and dreadful day of the Lord comes,” reads the Bible in Joel 2:31. The Toba people, who inhabited South America in the 16th century, believed that the eclipse was caused by the spirits of dead people taking the form of jaguars and attacking the moon, leaving it bloody. The Native American Hupa people believed that the moon possessed 20 wives and many mountain lions and snakes, and when the moon failed to feed the animals sufficiently, they would attack it and make it bleed. The eclipse ended when the wives intervened to offer protection.
Fewer superstitions may surround lunar eclipses in the 21st century, but these celestial moments still inspire both fascination at the sheer loveliness of the spectacle, and at least a little residual unease at the break in the normal, formal pattern of things.
“The rhythm of life is driven by astronomical changes,” says Alphonse Sterling, astrophysicist at NASA’s Marshall Space Flight Center in Huntsville, Ala. “We don’t feel the oscillations in cesium atoms, but we notice the sky. It takes the Earth 365 and a quarter days to go around the sun and 23 hours, 56 minutes and four seconds to spin on its axis. Part of that predictability too is the appearance of the moon. You have harvest moons and all of that stuff. When regularity isn’t there, it just throws us off.”
That regularity will return tomorrow at 7:49 a.m. E.T., when the last of the eclipse passes and the full moon reappears. In the eastern U.S., the moon will have already set by then, but in other, more westerly parts of the world, skygazers will see order restored, the moon unshadowed, and the lions, snakes, and jaguars appeased once more.
Correction: The original version of this story misstated the time it takes for the Earth to make a single rotation. It is 23 hours, 56 minutes, and 4 seconds, not 23 hours, 15 minutes, and 4 seconds.
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Write to Jeffrey Kluger at firstname.lastname@example.org