FYI.

This story is over 5 years old.

Tech

Set Your Alarm for the Shortest Lunar Eclipse of the Century

The Moon will be cast into blood red shadow early on Saturday.

On Saturday, April 4, the Moon will move into the Earth's shadow until it reaches total lunar eclipse. But there'll be two dark sides of the Moon for just a fleeting moment: at just five minutes, it's the shortest lunar ecli​pse of the century.

A total eclipse of the Moon occurs when the Sun, Earth, and a full Moon are lined up just so, such that Earth is in the middle and none of the celestial bodies are too far below or above the line. Our planet blocks the Sun from the Moon, casting it into shadow.

Advertisement

The result is a spookily red-coloured Moon, which varies in hue depending on atmospheric conditions, according to Mitzi Adams, an astronomer at NASA's Marshall Space Flight Center.

NASA explains the colour by suggesting you imagine standing on the Moon and looking at the Earth with the Sun behind it. You don't see a black Earth, but one ringed with fiery sunlight.

"As you scan your eye around Earth's circumference, you're seeing every sunrise and every sunset in the world, all of them, all at once," the agency's scien​ce site explains. "This incredible light beams into the heart of Earth's shadow, filling it with a coppery glow and transforming the Moon into a great red orb when viewed from Earth."

NA​SA adds that the Earth's atmosphere filters out a lot of the Sun's blue light, making the red colour particularly noticeable, earning this kind of eclipse the nickname of "blood Moon."

While the eclipse will start at 6:16 AM EDT, it won't reach total eclipse until 7:58 AM, and then it'll only last five minutes. That's much shorter than most lunar eclipses, which can last hours. You'll only be able t​o see the full red Moon in some of the US, Asia, and Australia, because of sunrise elsewhere.

But the good news is that, unlike some astronomical events, even city-slickers will be able to get a good view of the eclipse.

"This type of astronomical event is not 'best observed in a dark night sky,' [as so many are,]" Adams said in a teleconference with media. "You can definitely see this in the city, as long as you have a good view of the western horizon. The advantage, of course, is that if you're in a dark sky and the light of the moon is reduced, then you can see a lot of the stars around the moon better."

What makes this eclipse special, aside from the fact that it's so fast, is that it's the third in a series of four closely-linked lunar eclipses called a "tetrad." Each eclipse is about six months from the one before it; the first in the series was in April last year and the final one will occur in late September this year.

Tetrads are also quite rare, which has some people riled up (one American pas​tor in particular) that this one could be a sign of something biblical—like the end of the world as we know it.

Regardless, you probably want to set the alarm and get out to see the red Moon if you can. The last ​tetrad appeared in 2003-2004 and the next won't be for almost 20 years. In purely scientific terms, it'll be a neat celestial event.

Kaleigh Rogers contributed reporting.