There are a number of compelling reasons to catch the looming March 13-14 total lunar eclipse, which will be visible in the entire lower 48 states and greater Americas.
Perhaps the best one is that no two such eclipses are the same. That means, weather permitting, you'll witness something unique.
Total lunar eclipses occur when the sun, Earth, and moon are in alignment, allowing Earth to cast a shadow on the moon and block most sunlight from reaching the lunar surface. But our planet's atmosphere still allows red wavelengths of light to squeeze through, illuminating the moon in reddish, rusty, orangish, or crimson colors. Crucially, both the fickle conditions in Earth's atmosphere, and how deeply the moon passes through Earth's shadow, impact how light is ultimately projected onto the moon. This means different, and even unexpected, light shows.
"It's part of the thrill," Bennett Maruca, an astronomer at the University of Delaware who has witnessed a number of total lunar eclipses, told Mashable. "You don't know exactly what you're going to get."
Totality — meaning when the moon is totally within Earth's shadow — will begin at 11:26 p.m. PDT on March 13, 2025 / 2:26 a.m. EDT on March 14 / 06:26 UTC, lasting for 65 minutes. And the reddening progresses over hours, as the moon gradually moves into the Earth's shadow. (Technically, the eclipse starts with slight dimming on March 13 at 8:57 p.m. PDT / 11:57 p.m. EDT / 03:57 UTC). So, weather permitting, you'll have ample opportunity to see these bloody colors in action.
The first major factor at play in the amount of light and coloration illuminated on the moon is what's transpiring in our atmosphere, as sunlight must pass through our skies.
"Dust and clouds can affect the ultimate color of the moon during this event, which means that each total lunar eclipse ends up being somewhat unique and ultimately 'reflective' of the state of our own planet's weather," Eric Edelman, the planetarium director at Embry-Riddle Aeronautical University's Jim and Linda Lee Planetarium, told Mashable.
For example, if there's lots of dust in the atmosphere — such as expansive dust clouds from the Sahara desert — you'll generally get a redder eclipsed moon, Edelman noted. Storms play a role in impacting how the penetrating light hits the moon, too. And volcanic eruptions — which can blast prodigious amounts of ash and gas high into the atmosphere — can dim lunar eclipses, as volcanic particles impede light that would otherwise get refracted towards the moon.
"It can be quite surprising."
The other significant player in the moon's illumination is how far the moon travels into Earth's shadow (called the "umbra," and visualized in the short NASA video below). When passing closer to the shadow's center, the moon is illuminated with the darkest colors — to deep browns and even purples. When passing nearer to the shadow's edge, the moon is illuminated with rusty, orange colors. The coming March 2025 eclipse, then, may be more on the rusty spectrum.
But the moon won't be all the same color. Our expansive natural satellite, some 2,159 miles across, will be illuminated by different parts of Earth's shadow, meaning it will display some of those darker colors, as well as the lighter rusty colors. "That's one of the cool things about this eclipse," noted Maruca. "You see the color gradient."
Witnessing totality will mean a late night, or early morning, for many of us. But Maruca emphasizes it's worth it. It'll be a one-of-a-kind space light show. And you don't know exactly what you're going to get.
"It can be quite surprising," Maruca said.
