On August 11th, a giant moon rose above the sky. Not only was it a full moon, but it was also extraordinarily big and bright. The moon’s name is Sturgeon moon, and it is one of the four supermoons that occurred this year. 

How far away the moon is from Earth and how full it is are two elements that impact a moon's size. Even though the Moon is very close to Earth, it won't seem large and bright if it is a crescent moon (the previous full moon). Similarly, even if the moon is full, it won't appear larger than usual if it is distant from Earth. The moon's elliptical orbit affects the first element, which determines how close the moon is to Earth, and the lunar phase affects the second, which determines how full the moon is.

Credit: Getty Images: Michael M. Santiago / Staff

The distance between the Earth and the moon varies because of the moon's eccentric orbit around the planet. The "apogee," which is 405,500 kilometers from Earth, is the point in the elliptical orbit where the two are furthest distant from one another. The "perigee," which is 363,300 kilometers from Earth, is the point in the elliptical orbit where Earth and the moon come closest to one another.
An idea that is more widely understood is the Moon phase. The quantity of sunlight that the moon reflects changes as it revolves around the Earth, giving the moon changing forms. The full moon happens when the moon projects its complete body when it is in alignment with the Earth and the sun.

The moon looks much larger and brighter than on typical days when these two conditions coexist—namely when the moon is at perigee and fully reflects the sun—hence these sorts of moons are referred to as "supermoons." The remarkable thing about the supermoon is that each one is unique in terms of size and brightness since the moon's elliptical orbit shifts over time as a result of the gravitational pull of the sun and other planets. It is anticipated that the following supermoon will occur in August 2023. The next time you see a large moon, instead of snapping pictures of it, you may observe that it is entirely reflecting sunlight since it is at perigee.
 
 

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