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Supermoon 2021: 6 facts you need to know about the phenomenon

This infrequent lunar occurrence is worth staying up for.

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A full moon is already an event worth looking up for, but there’s an even more spectacular lunar phenomenon you should make time to see: the supermoon.

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In 2021, we’ll see two supermoons: one on the night of April 26 and one on May 26.

They’ll be visible throughout the night, with a peak shortly before midnight. So what exactly is a supermoon?

Here are 6 facts you need to know about supermoons.


A supermoon occurs when the Moon is at the closest point to Earth in its orbit, also known as its perigee.

Astronomers call supermoons “perigean full moons.”

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Since the full moon is so close to Earth during a supermoon, it can appear up to 30 percent brighter and 14 percent larger than a typical full moon.


Supermoons reach their peak late at night (11:31 p.m. Eastern for the April 26 supermoon). The well-known “Moon illusion,” which makes the Moon look larger near the horizon, means the supermoon may be more impressive around moonrise.

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The term “supermoon” comes from astrology, not astronomy.

It was coined by astrologist Richard Nolle in 1979, who predicted (incorrectly) that a supermoon would cause natural disasters.

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Astrological doomsaying aside, supermoons can increase the risk of tidal flooding. The Moon’s effect on tides is well known, and when at its closest point to the Earth, that effect is more pronounced.

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The Moon’s orbit isn’t static, so some supermoons are closer than others. The most striking supermoon of the 21st century is expected in 2052.

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Read more stories on astronomy here.

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