You don’t have to be an astronomy nerd to appreciate the cool science behind eclipses. In order for the human eye to see a solar or lunar eclipse, a very specific set of cosmic things need to happen—and they happen pretty rarely.
You might still remember the frenzy amongst Americans when we had the chance to see the last total lunar eclipse in January 2019. Some of my own friends loved it so much that they vowed to travel in order to see all future solar eclipses in the U.S. One even went down to Chile to see the solar eclipse that happened earlier this summer.
But a lunar eclipse, specifically, is a bit different. For one, a lunar eclipse can be seen almost entirely in the half of the Earth that is experiencing night. And you’ll be able to see the next eclipse (which is Penumbral) on January 10th, 2020. But before we dive into exactly how eclipses work—and how and where you can see it—let’s delve into a little bit of science, plus everything else we know about when the next lunar eclipse will take place.
What’s the difference between a lunar and solar eclipse?
All eclipses happen because of the interactions between the sun, moon, and Earth. What makes a lunar and solar eclipse different is, surprisingly, the position of the moon.
In August 2017, a huge chunk of America saw a total solar eclipse, which is when the moon moves between the Earth and the sun to block out the sun from view. In a lunar eclipse, though, the moon is in a different position.
A lunar eclipse happens because the Earth comes between the sun and the moon in such a way that the shadow of our planet is either partially or entirely covering our view of the moon—hence the lunar eclipse. It’s rare because the moon has to be in just the right part of its orbit for this to happen—and, yes, it can only happen when the moon is full.
What are the three types of lunar eclipses?
It might be a bit confusing to learn, but the three different types of lunar eclipses are: Penumbral, partial, and total. The most recognizable lunar eclipse type is the total eclipse, which happens when the entire moon passes through the Earth’s umbral shadow. In this case, the moon appears red or orange to us humans below—but more on that later.
Meanwhile, a partial lunar eclipse is when a portion of the moon passes through the Earth’s umbral shadow and it basically looks like a large part of the moon is covered by a shadow.
Here’s where things get even more complicated: A Penumbral eclipse happens when the moon passes through the Earth’s Penumbral shadow. In this type of eclipse, none of the moon is completely shaded by the Earth’s umbra (which is the fully shaded inner region of a shadow). This is the weakest type of eclipse—but still a pretty cool one to see if you can spot it.
Why does the moon look red during some eclipses?
You already know that a total lunar eclipse is when the moon passes completely under the Earth’s umbral shadow. However, the moon doesn’t completely disappear. Instead, it appears completely, just in shadows—and is hard to see if you are not looking for the eclipse, according to Space.com.
When a moon appears red during a total lunar eclipse (sometimes referred to as a blood moon), it looks even more mystical than when it is just in shadows. However, this can happen during the total portion of an eclipse because, while the moon is in complete shadow, a bit of light passes from the sun through the Earth’s atmosphere, and the colors make the moon look red.
It’s a pretty cool effect, but unfortunately, it will be a few years until we may see that again.
How many lunar eclipses are there in a year?
Typically, there are at least two lunar eclipses per year, but they vary in how strong they are. Because of the three different types of eclipses, no one lunar eclipse is alike. For example, the last total lunar eclipse was in January 2019, and we won’t get to see another total lunar eclipse in the U.S. until May 26, 2021, and then May 16, 2022 after that.
However, don’t lose hope. Because they do happen often and can be visible to a larger part of the world, you will likely be able to spot the next lunar eclipse long before then.
Do I need special glasses like a solar eclipse?
We all remember the hoopla over the special protective glasses that we had to wear during the last major solar eclipse in the U.S., but that’s not the case for a lunar eclipse. A lunar eclipse can be safely viewed with the naked eye, according to NBC News.
The only special equipment you might need is binoculars or a telescope, but that’s only if you want very close viewing. Basically, as long as you’re in the right place at the right time, you can just look up at the clear night sky and see the next lunar eclipse happening on January 10, 2020.