If there were ever a reason for aliens to visit Earth, it might just be to see an eclipse. From our unique spot in the cosmos, the Sun and Moon have a mathematical relationship with breathtaking consequences.
The Sun is about 400 times larger than the Moon, but it’s also about 400 times farther away, which means they can line up almost perfectly when they happen to overlap. The Earth is the only place we know of where a near-perfect total eclipse is possible, and no matter whether it’s a solar or lunar eclipse, the results are spectacular.
During a total solar eclipse, the Moon casts a massive shadow over a relatively small part of the Earth, but when a total lunar eclipse happens, the Earth’s shadow covers the entire face of the Moon. When things line up just right, the Moon is bathed in crimson light, an event lovingly known as a blood Moon.
You’ll have a chance to see one yourself this week, during the late evening of March 13 and/or the early morning of March 14, depending on where you’re located.
Why blood Moons happen during a total lunar eclipse
When a total lunar eclipse happens, the Earth falls into the Moon’s umbra (the darkest part of its shadow) and the Sun is blocked out, except for its corona atmosphere. A similar spectacle occurs during a total lunar eclipse, when the Moon transforms from its usual mottled gray to a menacing reddish hue.
It happens for the same reason the sky is blue and there are rainbows. When light gets refracted through a prism, white light gets fractured into all of its component wavelengths, and a rainbow of color spills out. Something similar happens as sunlight shines through the Earth’s atmosphere.
Every bit of sunlight that reaches the Earth’s surface passes first through the atmosphere. Along the way, molecules in the air scatter light on the bluer end of the spectrum while light on the redder end zooms on through. It’s the reason sunrises and sunsets paint the sky in brilliant colors and it’s the reason the sky is blue.
During a total lunar eclipse, the Moon gets only the light squeaking through the edges of the atmosphere. The blue light gets scattered away into the daytime sky and the red light remains to reach the Moon’s surface. The Moon turns red because it’s being lit by a planet’s worth of sunrises and sunsets all at the same time.
How to see the March 2025 blood Moon lunar eclipse
The March 2025 blood Moon lunar eclipse will be visible from the Earth’s Western Hemisphere, including the western half of South America and nearly all of North America. Locations farther east or west may still be able to see a partial lunar eclipse.
Unlike a solar eclipse (which requires special glasses, a pinhole camera, or other specialized equipment to view safely), anyone can look at a lunar eclipse with the naked eye, provided you have clear skies.
As the Moon first enters the Earth’s shadow, it will begin to dim slightly. When it enters into the umbra, you’ll see a dark disk begin to slide over top of the Moon’s face. Eventually, that shadow will cover the whole Moon and it will turn a copper color.
Over the course of about an hour, the red color will fade, the dark disk will slide off the face of the Moon, and the eclipse will end. The whole thing will last about six hours from start to finish, but the best part will be during totality, from approximately 2:26 a.m. until 3:31 a.m. ET on Thursday morning. Check local times to see when the eclipse will happen in your area.
Who knows, you might bump into Harry Vanderspeigle (star of Resident Alien, streaming now on SYFY) and the rest of the extraterrestrial rogues' gallery, here to see the lunar show.