If you're someone who enjoys their moonlight tinged with a bit of red, you've likely
A.) learned to never bring that up on a first date and
B.) had Jan. 21 circled on your calendar for a while now.
On that evening, skywatchers across North and South America will be treated to a rare lunar eclipse that coincides with a super moon. During totality, the lunar surface will appear a red ruddy color, giving this particular celestial occurrence the catchy moniker "super blood moon."
Why does all of this happen and why is this particular lunar event worth staying up for? Read on as we shed some (moon)light on the science behind this beautifully eerie phenomenon.
What exactly is a lunar eclipse?
A July 2018 lunar eclipse captured over Lake Wendouree in Victoria, Australia. That's Mars shining brightly at the top of the frame to the left of the eclipse. (Photo: Ed Dunens/Flickr)
A lunar eclipse occurs when the Earth, closely aligned between the sun and moon, casts its substantial shadow over the lunar surface. Unlike a total solar eclipse, when the moon's shadow (or umbra) completely blocks the sun for only a few minutes, the shadow of the Earth is much wider. Subsequently, this allows lunar eclipses to unfold over a much longer period of time.
When does the eclipse begin?
This month's event will start at 9:36 p.m. EST on Jan. 20 and conclude at 3:48 a.m. on Jan. 21. Totality, the point at which the surface of the moon will be completely covered by the Earth's shadow, will last for over an hour and start at 12:41 a.m. In other words, you should have plenty of time to duck your head outside and catch some piece of the lunar eclipse unfolding above!
Who will be able to see it?
Lunar eclipses are generally viewable by at least half the planet. Last year, the Eastern Hemisphere had a front-row seat to this century's longest total lunar eclipse (with totality lasting nearly two hours!), and this year all of North and South America, as well as portions of western Europe and northwest Africa, will be to view January's big event.
What makes this super moon eclipse special?
While lunar eclipses aren't exactly rare — 87 will take place over the course of the 21st century — only 26 will occur during a super moon. A super moon is the term given to a full moon or new moon that is at its closest point (roughly 238,000 miles) to Earth. Called perigee, this closeup makes the moon appear 14 percent larger and 30 percent brighter than a typical full moon.
What makes the moon appear red?
The phases of a lunar eclipse. (Photo: Christian Gloor/Flickr)
Unlike our own shadows, the one cast out an estimated 870,000 miles into space by Earth sports a ruddy red hue. This is due to indirect sunlight being refracted through Earth's thick atmosphere. While the shorter wavelengths are scattered, the longer wavelengths of red make it through and are cast onto the moon. As NASA explains, the color you're seeing is basically the culmination of every sunset and sunrise on Earth at once.
"You might suppose that the Earth overhead would be completely dark. After all, you’re looking at the nightside of our planet. Instead, something amazing happens. When the sun is located directly behind Earth, the rim of the planet seems to catch fire! The darkened terrestrial disk is ringed by every sunrise and every sunset in the world, all at once. This light filters into the heart of Earth's shadow, suffusing it with a coppery glow."
The lunar surface reflects that ruddy color back towards Earth and provides the eerie glow of red-tinged moonlight.
Why is it also called the super blood 'wolf' moon"?
Every full moon in the calendar year carries corresponding nicknames from different cultures around the world. For Native Americans, January's full moon is referred to as the "wolf" moon in recognition of the wolves that would howl in hunger outside their villages. Other names include the ice moon, cold moon, and where warmer months prevail in the Southern Hemisphere, the thunder moon.
Will I need special glasses to view the eclipse?
While solar eclipses require special glasses to view safely, you luckily won't suffer any scorched retinas while gazing up at a lunar eclipse. Moonlight, even the ruddy red variety, is harmless to the human eye.