Tonight, as you slip in some late-night Thanksgiving leftovers, take a moment to marvel at the full moon. Did you notice anything different? It’s subtle, but early Monday (Sunday night if you’re on the West Coast) the full moon should appear a little darker than usual. This is because you are witnessing a penumbra lunar eclipse, a celestial event in which the moon dives behind the faint outer shadow or penumbra of the Earth.
Penumbra eclipses are mild, almost imperceptible in some cases, says Jackie Faherty, an astrophysicist at the American Museum of Natural History in New York City. “It’s not something that’s going to slap you in the face.”
Sunday night’s eclipse will therefore not be as dramatic as a total lunar eclipse, in which the moon plunges into Earth’s dark inner shadow, called Ombra, making its surface blood red. It’s also not as striking as a partial lunar eclipse, in which the moon slips behind part of the shadow and looks like a space monster has taken a gigantic cookie bite from it.
And it’s not as impressive as a total solar eclipse, in which the new moon glides past the sun, leaving a wispy white halo shining in the daytime sky.
But the penumbra eclipse might still be worth your time to test how well you are in harmony with the night sky, Dr Faherty said. For our ancestors who lived without street lights or streetlights, the moon provided most of the useful light at night. If it has eased a bit, people have noticed.
But that perception has been partly lost as our reliance on moonlight has diminished. Dr. Faherty suggests using the penumbra eclipse to test your senses.
“Take on the lunar challenge,” said Dr Faherty. “Really look at him. Bask in the moonlight and see how it feels. Can you see the difference? “
The penumbra eclipse will be visible in North and South America, parts of East Asia, Australia and the Pacific, according to Space.com. It will begin at approximately 2:32 a.m. Eastern Time.
The best time to complete the lunar challenge will be at the “greatest eclipse,” which is 4:43 a.m. Eastern Time, when 83% of the full moon is in Earth’s penumbra shadow, according to NASA.
But if you’re still not convinced to watch the penumbra eclipse, maybe you can pull this nifty fact out of its appearance: it’s the harbinger of the next total solar eclipse. Lunar eclipses and solar eclipses are celestial peas in a pod. Once one appears, the other will follow two weeks later. And on December 14, a total solar eclipse will occur over parts of Chile and Argentina.