On Sunday, we'll be treated to a special cosmological treat. The year's biggest and brightest full moon will rise.
Technically there's only one supermoon a year, and this is it. The term refers to the time when the moon, which orbits Earth in a slightly elliptical trajectory, is at the absolute closest it can get while also being full. Other full moons have come very close (three already this year, with another coming on Sept. 9) and unofficially been granted the supermoon title, but Sunday's will be ever so slightly more magnificent.
"The size difference between even the dimmest and brightest full moon is only a bit more than 10 percent," Shawn Domagal-Goldman, research space scientist at NASA Goddard, said, "So the difference between other "supermoons" and this one isn't huge." But for him, Domagal-Goldman said, the event is a great excuse to take a moment to enjoy the beauty of the moon, something so often ignored in hectic day-to-day life.
Lunar events should be especially exciting to urbanites. "Normally, when cool stuff is happening in the night sky, we miss it because of the light pollution," Domagal-Goldman said. "But there's no such thing as too much light pollution to see the moon. All you need is nighttime and a clear sky. If you live in a city and want to share in the awe of the cosmos, this is the astronomical event for you."
To get those clear skies, Domagal-Goldman recommends going out right at moonrise when there's less likely to be cloud cover. And some optical tricks will help your viewing experience at that time, too. "It's going to look biggest and brightest to us when it's right next to the horizon," Domagal-Goldman said. When the moon is right next to things that we're familiar with, like trees and buildings, it looks much bigger than when surrounded by other astronomical bodies like stars.
It's true that most of us see Mars as the next frontier, but let's not forget that there's still lots to learn about our own moon. The Lunar Reconnaissance Orbiter continues to study and map the moon, tracking the footprints and rover trails left from Apollo and seeking out the best landing spots for future human missions. Researchers hope that the moon can teach us about the origins of our own planet.