Blood moon — next total lunar eclipse
"Blood moon" is the common name for a total lunar eclipse, when the Moon passes fully through Earth's shadow and takes on a reddish color instead of disappearing.
Why the Moon turns red during a total lunar eclipse
During totality, the Moon isn't in complete darkness — it's lit by sunlight that has passed through Earth's atmosphere and bent around the edge of the planet. Earth's atmosphere scatters away most blue light (the same effect that makes sunsets look red), so the light reaching the Moon is mostly red and orange, giving it that "blood moon" glow. How dark or bright red it looks depends partly on dust and clouds in Earth's atmosphere at the time.
Upcoming blood moons
How to watch a blood moon
A lunar eclipse is completely safe to watch with the naked eye — no filters or special glasses needed (that warning is only for solar eclipses). It's also easy: the Moon is large and moves slowly, so totality typically lasts from several minutes up to about an hour and a half, far longer than a total solar eclipse. Binoculars or a small telescope make the colour and surface detail more vivid, and a dark sky away from city lights helps, but the eclipse is visible from anywhere the Moon is above the horizon.
Common misconceptions
A "blood moon" is not a rare or ominous event in any scientific sense — it's simply the ordinary reddening of a total lunar eclipse, and it looks the same everywhere the Moon is up. It's unrelated to a supermoon (nearness to Earth) or a blue moon (the second full moon in a month), though the terms sometimes stack up in headlines when they happen to coincide.
Unlike a total solar eclipse, a total lunar eclipse is visible from the entire night side of Earth at once — no need to travel to a narrow path. For solar eclipses, see total solar eclipses, or browse every upcoming eclipse.