At a Glance

The moon reaches perigee, its closest point to Earth, on Tuesday.Because perigee coincides with the full moon, it's called a supermoon.One astronomer says most people won't be able to notice any difference in the moon.

Tuesday’s full moon will be the biggest and brightest of three supermoons this year.

Okay, it's not really bigger or brighter. The full moon appears that way because it will be at the point in its orbit that is closest to the Earth.

That point is called the perigee. When the moon reaches perigee on Tuesday, it will be 221,681 miles from Earth, or , USA Today reports.

It's called a supermoon when perigee coincides with the moon's full phase. According to the Farmers' Almanac, the was often called the snow moon by native tribes because snowfall was heaviest in that month.

On Tuesday, full moon will — a little less than seven hours after reaching perigee.

NASA explains that a full moon at perigee looks up to 14 percent bigger and 30 percent brighter than a full moon at its farthest point from Earth.

This will be the second time the moon has reached perigee this year. The first was Jan. 20. Because it happened during a total lunar eclipse, it was called the .

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The next supermoon will be on March 19.

Joe Rao, who writes for space.com, . He explains the phrase was created, not by an astronomer, but an astrologer, Richard Nolle in 1979. The term went viral in March 2011 when some incorrectly speculated that the moon's closeness to Earth may have affected the giant earthquake that hit Japan that month.

Rao writes that most people won't be able to discern any apparent change in size or brightness of Tuesday's moon. Still, he says the best chance to catch it is when the moon is rising or setting.