What to know about March’s full “Blood Worm Moon,” a total lunar eclipse

Astronomy fans are in for a treat this March as the full moon will appear to turn red during a total lunar eclipse.

March’s full moon, known as the Worm Moon, will pass into Earth’s shadow on the night of March 13, or early on March 14, depending on the time zone, according to NASA. This eclipse will be visible from Earth’s Western Hemisphere.

The Old Farmer’s Almanac details specific moonrise times for ZIP codes across the U.S. Local forecasts also include detailed information on how clear the night sky will be in various locations.

What is a lunar eclipse?

A lunar eclipse happens when the sun, Earth and moon all align so that the moon passes into the Earth’s shadow. During a total lunar eclipse, like the one happening this March, the entire moon will fall within the darkest part of Earth’s shadow. 

Each lunar eclipse is visible from half of Earth.

There are also partial and penumbral eclipses, which are when the sun, Earth and moon are not perfectly aligned. 

Why does the moon look red during the lunar eclipse?

With the moon in the shadow of the Earth, it will appear red-orange, according to NASA. Lunar eclipses are sometimes called blood moons because of the phenomenon.

During a lunar eclipse, the moon gets its red coloration because any sunlight that’s not blocked by the Earth is filtered through a “thick slice of Earth’s atmosphere” as it heads toward the moon’s surface, according to NASA. The more dust or clouds in Earth’s atmosphere during the total lunar eclipse, the redder the moon will appear.

“It’s as if all the world’s sunrises and sunsets are projected onto the Moon,” NASA explains in a blog post. 

This is the same phenomenon that makes the sky appear blue during the day. 

Why is March’s full moon called the worm moon?

The Worm Moon nickname may have come from the earthworms typically found as spring nears, according to the Old Farmer’s Almanac. Other research suggests the name may date back to writings from the 1760s about worms, or beetle larvae, coming out from bark as trees thaw from the winter. 

There are also other names for March’s full moon related to the transition from winter to spring. The first day of spring will be on March 20, just days after the Worm Moon. 

Other names for March’s full moon are the Eagle Moon, Goose Moon, Crow Comes Back Moon, Sugar Moon, Wind Strong Moon and Sore Eyes Moon.

What else can you see during the full Blood Worm Moon?

If there’s a bit of rain during the full moon, there may be a rare moonbow, according to the Old Farmer’s Almanac. It’s like a rainbow, but created by moonlight, rather than sunlight. Moonbows only happen when the full Moon is fairly low in the sky, so the phenomenon would be most apparent in the hours after sunset when the sky is dark. 

Viewers can also look to the western sky on the night of the total lunar eclipse to catch a glimpse of Jupiter and Mars, according to NASA. Constellations may also be easier to spot than usual as Earth’s shadow dims the Moon’s glow.