NASA says the term supermoon simply means a “full moon that is closer to Earth than average.”
“Since the moon’s orbit is elliptical, one side (perigee) is about 30,000 miles closer to Earth than the other (apogee),” NASA says. “The word syzygy, in addition to being useful in word games, is the scientific name for when the Earth, sun and moon line up as the moon orbits Earth. When perigee-syzygy of the Earth-moon-sun system occurs and the moon is on the opposite side of the Earth from the sun, we get a perigee moon or more commonly, a supermoon.”
At its closest point this weekend, the full moon will be 222,365 miles from Earth — on average, it’s 238,855 miles away, according to National Geographic. It will also “appear 16 percent larger than average and nearly 30 percent larger than the year’s smallest full moon.”
The November moon is set to be a real show-stopper: According to NASA, it is “not only the closest full moon of 2016 but also the closest full moon to date in the 21st century.” And it won’t be this close to Earth again until 2034.