WASHINGTON —

Thursday marks the third consecutive supermoon of the year.

No, it isn't a rare phenomenon. Advertisement

A supermoon is a full moon occurring at its closest point to Earth in orbit. Supermoons, while they may seem rare, actually occur three or four times a year and will always happen multiple months in a row.

This year, supermoons occurred in October and November – and the last one of the year will occur on Thursday, Dec. 4.

The distance between the Earth and the moon is actually always changing because the moon’s orbit is elliptical rather than circular.

When it's at its closest, it's called perigee. When it’s furthest away, it's called apogee. Supermoons happen when full moons are within 90% of perigee.

When supermoons occur, a phenomenon happens that might make som

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