LEILA FADEL, HOST:
Anyone with a clear sky overhead tonight could get a look at a celestial novelty - the supermoon.
A MARTÍNEZ, HOST:
So what makes this moon so super, you ask? Well, for an answer, we turn to an astrophysicist, Fred Espenak. He's a scientist emeritus for NASA's Goddard Space Flight Center.
FRED ESPENAK: The moon orbits the Earth in an elliptical orbit. When it's along the closest section of its orbit to the Earth, if that happens to coincide with full moon, then we call that a supermoon.
FADEL: Espenak is known as Mr. Eclipse, but he also happens to know a lot about supermoons.
ESPENAK: They're not extremely uncommon. There are at least three or four every year.
MARTÍNEZ: Tonight's supermoon is the first of four supermoons in a row. But just by looking up, how can you tell if the moon is truly super?
ESPENAK: I personally can't tell the difference between a supermoon and a regular moon, and I've been looking at the moon all my life. If you're looking in your kitchen and you had a 13-inch pizza and a 14-inch pizza, you can obviously see the difference. But now do a blind test. Some pulls out a 13-inch pizza. Can you tell if it's a 13 or 14 without measuring it? Probably not.
FADEL: Still, Espenak says, it's worth craning your neck to catch a glimpse.
ESPENAK: The moon is beautiful to view in the nighttime sky, and it's something that people can see whether they're in a light-polluted city or out in the country.
MARTÍNEZ: Alright, write this down. The next three supermoons will be September 18, October 17, and November 15. Plenty of time over the next several months for amore.
(SOUNDBITE OF SONG, "THAT'S AMORE")
DEAN MARTIN: (Singing) When the moon hits your eye like a big pizza pie, that's amore. Transcript provided by NPR, Copyright NPR.
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