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Updated: Sun, 13 Jul 2014 07:28:59 GMT | By The Associated Press, cbc.ca

Supermoon lights up sky during close passage to Earth



A supermoon rises over the Oregon Convention Center in Portland, Ore, Saturday, July 12, 2014. (© AP Photo/The Oregonian, Mike Zacchino)

A supermoon rises over the Oregon Convention Center in Portland, Ore, Saturday, July 12, 2014. (AP Photo/The Oregonian, Mike Zacchino) MAGAZINES OUT; TV OUT; LOCAL TELEVISION OUT; LOCAL INTERNET OUT; THE MERCURY OUT; WILLAMETTE WEEK OUT; PAMPLIN MEDIA GROUP OUT Mike Zacchino/The Oregonian/The Associated Press

The full moon on Saturday appeared to be unusually big. In fact, it was what's known as a supermoon.

That's the nickname for full moons that happen when our celestial neighbour is relatively close to Earth. That distance varies because the moon follows an elliptical orbit. When it's close and full, it appears bigger and brighter than normal, although in fact the difference can be hard to detect.

If you saw Saturday's moon close to the horizon it may have seemed huge, but that's just an illusion caused by its position in the sky.

Two other full moons this summer, on Aug. 10 and Sept. 9, are also supermoons.

It's not all that unusual to have a supermoon. There were three in a row last year.

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