Supermoon Graces Sky Monday Night

If one is wondering why his Facebook newsfeed seemed to be full of amateur shots of the Moon Monday night, then he might be one of the few who is not making a fuss over the supermoon, which is said to be the biggest ever from our vantage point on Earth for nearly seven decades.

As The Washington Post noted that the term "supermoon" is arbritrary -- and the term was not used in such a way until it was defined by astrologist Richard Noelle, who began using it in the 1970s. Still, his definition was not quite so astronomical -- it is merely a new or full moon that happens when the Moon is within 90 percent of its closest approach to the Earth in a given orbit.

Yet, actual astronomers are not too fond of using the term supermoon, because when everything is "super," then none really is. Instead, they often use the term perigee -- and a perigee moon occurs a few months out of every year.

The current season alone, for example, is going to see five supermoons, including the moons of Sep. 16, Oct. 16, Nov. 14, Dec. 16 and Jan. 12, 2017. Yes, supermoons are actually more common than you might think -- so while they are not as rare as say a total solar eclipse or even the closest approach of Mars in 60,000 years.

So how does one explain the existence of the supermoon, and why is it that everyone is making a big fuss out of it?

The Moon circles the Earth every four weeks. But because the orbit is not circular, but rather elliptical, there is a point every month when it is at its closest point to Earth, and there is a point when it is furthest. There are rare times when the rotations keep the satellite so close to Earth that it becomes "super."

News Australia also pointed out that the opposite, naturally, is called a "micro moon."

On Monday night, however, people see the Moon at its closest -- it will take another 18 years for them to see another one like it again.