Learn what to look for in the night sky with today's Nerdy Curio from Stardate. We give full Moons all kinds of names. The full Moon of January, for example, traditionally is known as the Old Moon, Wolf Moon, or Moon After Yule. A second full Moon in a month is known as a Blue Moon. And a full Moon that occurs when the Moon is especially close to Earth is a supermoon.

And there’s a supermoon coming on Sunday night. The Moon will be full only half a day before it reaches its closest point to Earth for its current orbit — and its third-closest point for the year.

And it coincides with a total lunar eclipse. The Moon will pass through Earth’s long shadow. That will make it appear dark orange or red. The entire eclipse will be visible across all of North America, beginning Sunday evening.

The Moon’s orbit around Earth is lopsided, so the Moon’s distance varies by about 30,000 miles. Its closest approach is known as perigee. And the Moon will reach that point on Monday — about 222,000 miles from Earth.

Perigee doesn’t always occur at full Moon. Instead, on average it shifts by a couple of days per cycle. So it can occur when the Moon is full, new, or any phase in between.

The way “supermoon” is used varies. Some use it to mean the closest full Moon of the year — which will occur next month. Others use it for full Moons that are within a certain distance of Earth.

However it’s used, enjoy the supermoon — one that’ll be fully eclipsed — an event that’s come to have its own name: a Blood Moon.

Script by Damond Benningfield

Aired January 18, 2019

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