ROCHESTER, N.Y. (WROC) — If it can be seen between the passing clouds Wednesday night, the moon will look larger than life. This is because the moon will be reaching its full phase, aka a full moon, just hours apart from when the moon makes its closest pass to the earth, also known as the perigee.
This combination of events is known as a super moon.
In order to understand how this happens, we need to dive into how the phases of the moon work, and how the moon orbits the earth. Both are on different cycles, which makes this an uncommon event but not rare as this can, and has, happened multiple times a year.
Starting with the moon’s orbit, much like the Earth’s, it’s not a perfect circle. Objects in space have what’s known as an elliptical orbit, or an oval-shaped orbit.
Unlike the Earth though, the moon only takes 27.32 days to complete its journey versus the 365.25 that it takes the Earth. During this time, the moon reaches two critical points in its orbit. One is the apogee when the moon reaches its furthest point away from the earth at approximately 251,600 miles away. The other is the perigee, which is when the moon is closest to the earth at only 224,000 miles away.
Now, the phases of the moon are a bit more complicated as there are eight of them. The one that we’re most concerned with in regards to the super moon is when it’s in the “Full Moon” phase so we’ll focus on only that for now. A full moon only happens every 29.53 days, so just short of a month. This is slightly longer than the time between the perigee of the moon’s orbit, meaning the orbit of the moon and the phases of the moon are out of sync.
Why are they out of sync? Well, that’s because the moon’s orbit and its phases are influenced by different forces.
The orbit of the moon is influenced by Earth’s gravitational pull on the moon itself. While the phases of the moon are influenced not just by the orbit of the moon around the Earth, but also by the orbit of the Earth around the sun. Since the Earth and the moon aren’t in sync with each other’s orbits and due to the fact both orbits tilt in different directions it takes just that much longer for the phases of the moon to complete a full cycle. Simple right?
Due to these differences, we don’t always get a super moon. Though usually, we get at least a few every year. In 2022 specifically, we get four!
Wednesday night’s super moon will be the third, with the final one of the year happening on August 11, 2022. After that, we won’t see another ‘larger than life’ moon in the sky until August 1, 2023.