Perigee Supermoon lights up the sky after 68 years


Prameela Kottapalli

While full moons occur once every month, supermoons- characterized by their larger-than-average size and their remarkable brightness- light up the night sky only once every 411 days. “It’s fun to go outside and look at the moon when it’s bigger, and it also will look brighter as a result,” Dr. Nelson said. “Not just as an appearance, but it actually will be brighter than your average full moon.”

by Meena Gudapati and Anya Weaver

Every 29.5 days, the full moon shines in the night sky, illuminating the darkness with its glow. While astronomer and casual observers alike have many opportunities to study the moon at its fullest, tonight’s night sky features something unique- something astronomers call the supermoon.

The word “supermoon” refers to a full moon that is larger than average. Tonight’s moon will be especially large because the moon is full at its perigee, the point at which it is closest to Earth in its ellipse-shaped orbit. The last time the moon was this close to the Earth was in 1948. Astronomers speculate that this year’s supermoon will be 14 percent larger and 30 percent brighter than when the moon is at apogee, it’s furthest point from earth.

The moon will reach the crest of its full phase at 5:52 a.m. and will reach perigee within 1.5 hours of the crest.

The phrase “supermoon” was previously used to only refer to this type of moon, but it has evolved into a looser term merely referring to size, so a perigee supermoon will often be referred to as an “extreme” supermoon. Supermoons occur about once every 411 days.

“[Supermoons] are actually pretty common,” astronomy teacher Dr. Eric Nelson said. “But this one, in terms of the terminology we use for supermoons, is unusual because it is so close to the actual perigee position rather than just being closer than the mean.”

Tonight’s moon will be visible anywhere on Earth where it is dark and relatively cloudless.

Jimmy Lin (11) did an astrophysics research internship at University of California, Santa Cruz in the summer of 2015.

“I think it’s definitely great that this new story is helping astronomy reach the general public, and I think it’s a great opportunity for the common person to get interested in a national phenomenon that also has a scientific understanding behind it,” he said.

This one, in terms of the terminology we use for supermoons, is unusual because it is so close to the actual perigee position rather than just being closer than the mean.”

— Dr. Eric Nelson

Sneha Bhethanabotla (12) has an interest in astronomy and is aware of the supermoon phenomenon.

“I wish the school would organize an event to view supermoons. Not a lot of people have the time to see it, so if there’s a school organized event it would be cool,” Sneha said. “More people would see something pretty.”

Although supermoons as large as the one that was visible are relatively uncommon, supermoons in general occur relatively often. The next supermoon will occur on Dec. 14.

Observers who miss either of these supermoons will have many opportunities in the near future to witness other astronomical events. The next lunar eclipse, or the passing of the Moon into the Earth’s shadow, will occur on Feb. 11 of next year and will be visible in North America, although it will be a partial eclipse. 

The next solar eclipse, or the passing or the Moon between the Sun and the Earth, will occur Feb. 26, although the next solar eclipse easily visible from North America will occur Aug. 17 of next year and will be a total eclipse.

This piece was originally published in the pages of The Winged Post on November 16, 2016.