On the night of March 13-14, a “blood moon” total lunar eclipse will be visible from North and South America, Western Europe, far Western Africa, and New Zealand.
To prepare for this stunning event, here are seven interesting facts about lunar eclipses.
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1. Total lunar eclipses have much wider paths of totality than total solar eclipses.
This century, there will be 85 total lunar eclipses. A given geographic location on Earth’s surface will experience an average 40 to 45 total lunar eclipses, or about one every 2.3 years. In contrast, a specific location will witness a total solar eclipse once every 375 years, on average.
The reason for the large disparity is simple: To see a total solar eclipse, you must be fortuitously positioned along the path of the moon’s dark shadow (the umbra), which might extend for many thousands of miles but cannot be any wider than 167 miles (269 kilometers) in diameter. In contrast, the region of visibility for a total lunar eclipse extends to more than half of Earth, allowing billions to partake in the lunar show.
2. More than a billion people will be in the viewing zone for the March 13-14 total lunar eclipse.
To determine the visibility of the total lunar eclipse on March 13-14, we took into account the populations of North and South America, 17 nations in western portions of Europe and Africa, New Zealand and eastern Siberia. From this, we have determined that potentially as many as 1.36 billion people will be able to see the moon become completely immersed in Earth’s dark umbral shadow. We say “potentially” because the weather for some parts of the globe will be cloudy or unsettled, hence precluding a view of this shady celestial drama.
3. The temperature on the moon plummets during a total lunar eclipse.
When Earth’s shadow sweeps across the lunar landscape, the temperature plummets. In fact, the resulting “thermal shock” may cause lunar rocks to crumble and gas to escape from within the moon. Normally, as the sun slowly sets from the moon’s perspective, the drop in temperature is gradual. But if sunlight is shut off when the sun is high in the lunar sky, the drop is much more rapid — over a span of just 10 to 30 minutes.
During a total lunar eclipse in February 1971, temperatures were monitored at two Apollo landing sites. At the Apollo 12 site on the Ocean of Storms, the temperature dropped from 168.3 to minus 153 degrees Fahrenheit (75.7 to minus 102.8 degrees Celsius) — a change of 321.3 F (178.5 C). At the Apollo 14 Fra Mauro site, the temperature dropped from 154.1 to minus 153 F (67.8 to minus 102 C) — a change of 307.1 F (169.8 C).
4. The totality phase of a total lunar eclipse can’t last longer than 107 minutes.
The longest duration of totality for a lunar eclipse is 107 minutes. This can happen when the moon crosses through the middle of Earth’s shadow, when the moon is at or very near apogee, the farthest point in its orbit from Earth. When the moon is near apogee, it is moving more slowly and needs more time to cross our planet’s shadow.
The total lunar eclipse of July 16, 2000 — which was visible in the Pacific Ocean, eastern Asia and Australia — was one of the longest on record, lasting 106 minutes, 25 seconds. On Aug. 13, 1859, totality lasted three seconds longer. It will take thousands of years — until Aug. 19, 4753 — for there to be a longer total eclipse, which will last 106 minutes, 35 seconds, according to astronomer Jean Meeus.
As far as the shortest totality for a lunar eclipse, theoretically, it could last just an instant. In recent years, the shortest total lunar eclipse occurred on April 4, 2015, when the duration of totality was less than five minutes.
5. The term “blood moon” comes from a prophecy.
In recent years, the term “blood moon” has been used to describe a total lunar eclipse. The phrase comes from a book written by a pastor, who claimed that beginning in April 2014, a series of four consecutive lunar eclipses — all coinciding with Jewish holidays, with six full moons in between and no intervening partial lunar eclipses — was an omen of the end times. The eclipse series is called a lunar tetrad and is very variable with time.
For instance, Meeus points out that no tetrads occurred when Louis XIV was king of France, yet from 1909 to 2156, no fewer than 16 tetrads will have taken place. And during a 2,000-year interval, 25 of these began between March 16 and May 15, meaning there have been other periods in history when tetrads coincided with Jewish holidays, yet the world didn’t end.
So the “blood moon prophecy” is nothing more than a fallacy and should be filed away with the nonsensical prediction that “Rapture” and judgment day were to take place on May 21, 2011.
6. A lunar eclipse saved Columbus.
On his fourth and final voyage to the New World, Christopher Columbus and his men were, for a time, marooned and hungry on the north coast of Jamaica. The Indigenous Arawak people were becoming tired of their demands.
But “The Almanach Perpetuum,”written by Abraham Ben Samuel Zacuto, came to Columbus’ aid, predicting a lunar eclipse for Thursday, Feb. 29, 1504. Knowing this, three days earlier, Columbus warned the Indigenous people that he would take the moon away if they did not cooperate with his expedition.
He wrote:
“It began before sunset, so I could observe only the end of it, when the moon had just begun to return, and it must have been two and a half hours after sunset.”
When the Indigenous people implored him to bring back the moon, Columbus drew aside and pretended to pray. As the moon began to emerge from the Earth’s shadow, they cheered and hurried away to bring food for the ill and starving men. Zacuto’s work thus saved the admiral’s life and that of his crew.
7. The next lunar eclipse will be the “opposite.”
After this month’s eclipse, the next total lunar eclipse will take place on Sept. 7. Think of it as the flip side of the lunar eclipse of March 2024. On this occasion, all the places in the Eastern Hemisphere that didn’t get a view of the previous eclipse — central Africa and eastern Europe to eastern Asia, Japan, Indonesia and Australia — will be in perfect position for this event. Meanwhile, the Americas will see none of it because the moon will be below the horizon and it will be daytime during this eclipse.
On March 3, 2026, North Americans will get another opportunity to view a total eclipse. However, for observers in the Eastern time zone, the moon will set during the dawn’s early light during the total phase. Places in the middle of the country will be able to catch the moon emerging from Earth’s shadow as it sets, while for the Western part of the country, the eclipse will be visible from start to finish. Hawaiians will see the moon almost overhead as totality takes place in the hours after midnight.
On Aug. 27-28, 2026, an “almost” total lunar eclipse will occur. This eclipse favors much of North America, though far Western areas (including Hawaii) will see the moon rise already within Earth’s dark umbral shadow. At mid-eclipse, 93% of the moon will be immersed in the umbra, leaving only the uppermost part of its disk in view.
The next time North America will see a total lunar eclipse with viewing circumstances comparable to this month’s eclipse, it will be an event that will cross over from one year to the next — from Dec. 31, 2047, to Jan. 1, 2048. That entire event will be visible from coast to coast, with totality lasting 57 minutes.
Honorable mention
And finally, in January 1972, several dozen people were injured in the Cambodian capital of Phnom Penh when hundreds of troops across the city let off a fusillade of bullets at a total eclipse of the moon. The soldiers, both in the streets and at guard posts, fired their weapons, trying to prevent the moon from being eaten by a mythical monster frog called Reahou. According to an ancient Cambodian legend, the giant frog wants to eat the moon and must be stopped. I guess we can call this a ribbeting occurrence!
Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers’ Almanac and other publications.
