Super Moon Times Three
By Addah Arcilla | August 19, 2014 11:55 AM EST
Year 2014 is pretty phenomenal when it comes to super moon sightings. Last Sunday's super moon was the second of three super moons that we were expecting this year. People from the entire world looked up in the sky and marveled at its magnificence and luminosity.
So what's a super moon again?
A "super moon" happens when a moon becomes full on the same day as its perigee or the point in its orbit when it's closest to earth. The astronomical community refers to this as the "perigee" moon.
Full moons have different sizes because the moon follows an elliptical orbit. Because the moon's orbit around the earth is shaped like an egg, there are times when the moon is at its perigee--closest to the earth--or at its apogee--point farthest from the earth. Full moons that occur on the perigee side of the moon's orbit appears extra big and bright.
According to Geoff Chester of the U.S. Naval Observatory, perigee moons are not at all that unusual even those that appear in rows. In fact, full moons appear at its perigee every 13 months and 18 days. Year 2011 also had three perigees in a row, but only one received attention from the media.
While it may occur often enough, in reality it is not easy to spot the difference between a perigee moon and an ordinary full moon. The 30% difference in brightness can be masked by clouds and haze. Our eyes also cannot detect the few hundred miles or kilometers difference in the distance of the moon from the earth. And with no comparison to provide a sense of scale while it hangs overhead, it is easy to mistake one full moon from another.
According to Chester, the best time to see a super moon is when the moon creeps over the horizon. This makes the silvery orb look larger as it poses with trees, buildings and other foreground objects. Astronomers and psychologists call this the moon illusion. And although the phenomena is not fully understood, it makes for the most picturesque shots of the moon.
So if you happen to miss last Sunday's big show, fret not, because the super moon will once again brighten up the sky for the last time--for this year, at least on September 9.