Supermoons

A supermoon is a full moon that looks bigger and brighter than usual. It happens when the Moon is at its closest point to Earth in its orbit. The Moon does not travel in a perfect circle. Its path is shaped more like an oval. When it is closest to us during a full moon, we call it a supermoon.

Why the Moon's Distance Changes

The Moon orbits Earth in an oval-shaped path called an ellipse. At its closest, the Moon is about 226,000 miles away. At its farthest, it is about 253,000 miles away. That is a difference of about 27,000 miles. When the Moon is closest and also full, it appears about 14 percent bigger than normal.

How to Spot a Supermoon

A supermoon looks biggest when it is near the horizon. That is when buildings and trees give you something to compare it to. It also appears about 30 percent brighter than the faintest full moon. Supermoons happen a few times each year. They are a great reason to go outside and enjoy the night sky.

Fun Facts

• The word supermoon was first used in 1979 by an astrologer, not an astronomer.
• A supermoon can light up the ground enough to cast shadows at night.
• There are usually 3 to 4 supermoons each year.

Did You Know?

Even though a supermoon looks much bigger, it is only about 14 percent larger in the sky than a regular full moon. Most people cannot tell the difference without comparing photos.