As the sun begins to set in the west tonight, the moon will rise in the east. This happens every night, but this evening a special occurrence will take place in the sky.


Perigee full moon, or supermoon as it has come to be known in recent years, will be in the sky tonight.


The moon will come within 222,000 miles of Earth and turn full around 7:30 a.m., making it the best time to view.


Perigee means when the moon is nearest to the Earth, said Darlene Smalley, program director at the USC Aiken DuPont Planetarium.


Supermoon was coined in 1979 by astrologer Richard Nolle. Nolle defined the term as “a new or full moon which occurs with the moon at or near (within 90 percent of) its closest approach to Earth in a given orbit.”


Basically, tonight’s full moon will be bigger and brighter. In fact, the moon will appear 14 percent bigger and 30 percent brighter than usual, according to NASA.


While the moon will appear 14 percent larger normal, skywatchers won’t be able to notice the difference with the naked eye. Still, astronomers said it’s worth looking up and appreciating the cosmos.


“It gets people out there looking at the moon, and might make a few more people aware that there’s interesting stuff going on in the night sky,” Geoff Chester of the U.S. Naval Observatory said in an email to the Associated Press.


Supermoons are not a rare event. Each year, there are three perigee full moons.


“Perigee full moons occur in three consecutive months out of the year,” said Smalley. “This year it will occur in May, June and July.”


In recent years, perigee full moons have occurred around the time of natural disasters, such as the 2011 earthquake in Japan. This was followed by people blaming the supermoon for the destruction.


The moon is not to blame, Smalley said.


The only thing that will come as a result of the perigee full moon will be higher and lower tides. This occurs as the moon’s gravitational pull will be stronger due to the moon being closer to the Earth.


But, will you really be able to tell a difference between a full moon and a perigee full moon? Smalley said that, if you were to take a picture of the moon at perigee and a picture of the moon at a later date, you would see a difference.


The official moonrise will be Saturday at 7:56 p.m., and the moon will set Sunday at 5:26 a.m.


For those who miss the opportunity to see it tonight, there will be another chance to see it July 22.


The Associated Press contributed to this article.


The moon illusion

Due to a little-understood optical effect called the moon illusion, the full moon can seem huge when rising behind distant objects on the horizon. A supermoon could appear especially impressive.


Source: www.space.com