Total Lunar Eclipse Jan. 20th-21st

This Sunday night into Monday morning (January 20th-21st), the moon will pass into the shadow cast by Earth causing a total lunar eclipse. During a lunar eclipse, a full moon will turn a rusty color. What's even better is that during this lunar eclipse, the moon will be near its closest approach to Earth, making it a supermoon. Be sure to make plans to view this total lunar eclipse since it will be the last total lunar eclipse visible in the United States until 2022.

Why do we have lunar eclipses?

The simple answer is “because the moon sometimes passes through the shadow of Earth.” But there’s more to it than that. For one, it has to happen during a full moon. When the moon is full, it means the sun, Earth, and moon are in alignment. 

Joss Fong/Vox

Now, you might be thinking: “Why don’t we have lunar eclipses every full moon?” The answer to that questions is that the moon’s orbit isn’t perfectly matched up with Earth’s; it’s tilted 5 degrees. Which means that during most full moons, the shadow misses the moon. 

You don’t need any special equipment or protective glasses to view it (unlike with a total solar eclipse). But a pair of binoculars will give you a better, more detailed view of the moon’s geography as it darkens in shadow.

What’s a supermoon?

The moon’s orbit around Earth is not a perfect circle. It’s an ellipse, a saucer shape that’s longer than it is wide. As the moon follows this orbit, it’s sometimes closer to Earth and sometimes farther away. At perigee (the closest spot in its orbit to Earth) it’s around 31,068 miles closer to Earth than at apogee (when it’s farthest away).

NASA

Meanwhile, we see different phases of the moon — full, crescent, waxing, and waning gibbous — depending on if the sun-facing side of the moon is facing the Earth.

A supermoon is when these two cycles match up and we have a full moon that’s near its perigee. The result is that the full “super” moon appears slightly larger and slightly brighter in the sky. This occurs about one in every 14 full moons. The difference between a normal full moon and a supermoon isn’t all that significant though, and sometimes not even distinguishable to an untrained human eye. 

Why does the moon turn red during a lunar eclipse?

During a total solar eclipse, like the one North America saw in 2017, the entire sun turns black, revealing the sun’s atmosphere. What happens during a total lunar eclipse is a bit less dramatic, but beautiful nonetheless.

When sunlight passes through the atmosphere, the gases trap and scatter the blue light in the spectrum. (This is why the sky appears blue.) The red, orange, and yellow wavelengths pass through into Earth’s shadow and get projected onto the moon. So basically a total lunar eclipse is like projecting the sunset and sunrise onto the moon.

When can I see this?

The Jan. 20-21, 2019 total lunar eclipse will last 1 hour and 2 minutes and the full experience (from the start of the partial eclipse to the end) will last 3 hours and 17 minutes. Below is a chart of the timeline, phases, and events for this total lunar eclipse. The best time to view this in Arkansas is between 10:41-11:43 pm this Sunday night!

Get ready for this special nocturnal hour where the full moon will become fully tinted with the red-orange color of sunset. Be sure to send Arkansas Weather any pictures you capture! You can send them to us on Facebook or Twitter!