A supermoon is pretty but three supermoons in a row is nothing short of phenomenal, and that's what the summer skies will treat us to this year.
The first one is set to happen soon, that is, July 12, Saturday. This will be followed by a supermoon next month on August 10, which is said to be the biggest of the three. September 9 marks the last of the three supermoons to grace our skies this year.
In scientific circles, a supermoon is called a perigee full moon, or a full moon that occurs at or near its perigee. The perigee is the point at which the moon is closest to the Earth. At this point, the moon is around 50,000 kilometers closer to our planet than when it is at its apogee, or the point farthest away from Earth, making it appear larger than it normally is.
On Friday, the moon will be closest at 8:28 GMT, with the full moon occurring three hours later at 11:25 GMT. August will have the biggest supermoon, with the moon becoming full at 18:09 GMT, only a few minutes after perigee at 17:44 GMT. On September 9, those who want to take supermoon photos can camp out until the wee hours of the following morning until 1:38 GMT for the full moon and 3:30 GMT for perigee.
"Generally speaking, full moons occur near perigee every 13 months and 18 days," says [video] Geoff Chester of the National Aeronautics and Space Administration (NASA). "In fact, just last year, there were three perigee moons in a row, but only one was widely reported."
Chester was referring to the supermoon of June last year, which was widely reported by the press for being 30% brighter and 14% bigger than the other moons of 2013. The June supermoon was sandwiched between the supermoons of May and July, but only the June 23 occurrence gathered widespread publicity.
Chester attributes this to the fact that supermoons are actually difficult to distinguish from a regular full moon. He says that a 30% increase in brightness can be easily masked by a cloudy sky or haze. He also thinks that any reports of a supermoon this summer will most likely be "illusory."
This illusion stems from the fact that full moons appear largest when they are hanging low from the horizon. Although astronomers and psychologists still haven't found an explanation for this, most agree that the moon looks larger than usual when it beams through foreground objects such as buildings and trees. When a perigee full moon amplifies the illusion, the moon can look unnaturally large to us viewers from below.