What Is a Blood Moon? | Total Lunar Eclipse | The Old Farmer's Almanac

What a Blood Moon Is—and Isn't


Total lunar eclipse

Photo Credit

Separating Lunar Fact from Fiction

Print Friendly and PDF
The 2024 Old Farmer's Almanac

Read more about the Total Solar Eclipse in The 2024 Old Farmer’s Almanac!

Get A Copy

The next Blood Moon will occur on March 14, 2025. What exactly IS a Blood Moon? There are boatloads of celestial hype about this phenomenon, as well as the reference to a strange prophecy. I’ll help you separate fact from fiction.

What Is a Blood Moon?

In simple terms, a Blood Moon is another name for a total lunar eclipse—like the one taking place on March 14, 2025.

During a lunar eclipse, the Earth passes between the Sun and the Moon, blocking the Sun’s rays. The Moon will be 100% obscured during this eclipse. However, the Moon isn’t completely dark. What we see from Earth is the Moon slowly darkening and changing color over a few hours from bright white to an orange-red.

What is it Called a Blood Moon?

The Moon turns a reddish hue when it’s completely submerged in the Earth’s shadow. Call us picky, but we wouldn’t ever describe the color as “bloody.” The fully-eclipsed Moon actually becomes orange or coppery like a penny. 

While most of the sunlight is indeed blocked, some rays bend around the edge of Earth and reach the Moon’s surface. Earth’s atmosphere scatters the blue/green colors (short wavelengths), but the orange/red colors (long wavelengths) reach our eyes. It’s similar to a sunset. 

Although not as awe-inspiring as a total solar eclipse, a full eclipse of the Moon is still an amazing astronomical sight. 

the position of the earth, sun, and moon during a total lunar eclipse
Image: NASA

The Blood Moon Prophesy

We’ve heard all kinds of strange theories about a “Blood Moon.” Back in 2014–2015, some religious preachers made prophecies about a rare series of four consecutive total lunar eclipses (Blood Moons), claiming it was a sign of the beginning of the end times. They quoted the Book of Joel which said that “the sun will turn into darkness, and the moon into blood, before the great and terrible day of the Lord comes.” 

The Bible also references a Blood Moon in Acts 2:20 and Revelation 6:12. In the latter, the verse says, “And I beheld when he had opened the sixth seal, and, lo, there was a great earthquake; and the sun became black as sackcloth of hair, and the moon became as blood.

Well, the media went a little crazy hyping these end-of-the-world prophesies. Clearly, the world did not end!

The “Blood Moon” is not a technical term used in astronomy. It’s really more of a popular phrase, perhaps because it sounds so dramatic. Once again, the term simply refers to a total lunar eclipse. Yep, that’s it.  So, don’t let the term “Blood Moon” throw you.

More About Eclipses

Lunar eclipses shouldn’t be confused with solar eclipses. Both involve the Moon, but are different events.

A total solar eclipse is the greatest celestial event the human eye can behold. It’s when the Moon passes between the Sun and the Earth, blocking out the Sun for a short period of time. See the next total solar eclipse date.

By the way, an animated aurora borealis might hold second place. An exploding meteor, called a bolide, or a brilliant, colorful one, called a fireball, might hold third place. And a brilliant comet like Hale-Bopp that came around 20 years ago might be the fourth greatest spectacle.

A lunar eclipse is interesting, but it doesn’t quite have that make-you-gasp, pedal-to-the-metal glory. Moreover, the thrill is the solar totality. That’s when flames (“prominences”) shoot off the Sun’s edge, and its corona leaps far across the sky, and stars come out, and many people weep. A partial solar eclipse, which requires eye protection, offers none of those things. That’s why “total” is the critical eclipse adjective.

But lunar eclipses are different. When the Moon is 99% eclipsed, it’s quite fascinating. Nothing extra happens when the Moon plunges into the final one percent of Earth’s shadow. In fact, some might argue that 99% is more visually spectacular because there’s then one final spot of white on the Moon’s edge, which makes its overall coppery color more dramatic.

Bottom line: Totality is far less critical when it comes to lunar eclipses. And you may enjoy a lunar eclipse from anywhere on the planet where it’s nighttime! 

→ See all of the upcoming solar and lunar eclipse dates

About The Author

Bob Berman

Bob Berman, astronomer editor for The Old Farmer’s Almanac, covers everything under the Sun (and Moon)! Bob is the world’s most widely read astronomer and has written ten popular books. Read More from Bob Berman

No content available.