Home > News > Mark Your Calendar -- "Super Moon" of November 14th Will Be the Largest Since 1948
Mark Your Calendar -- "Super Moon" of November 14th Will Be the Largest Since 1948 Posted by Guy Pirro on 11/5/2016 5:46 PM
Seen from the roof of the Memorial Library on the University of Wisconsin - Madison campus, a Super Moon rises in the nighttime sky behind the "Wisconsin" statue atop the dome of the Wisconsin State Capitol. The term "Super Moon" refers to a point when when the Moon reaches its full phase at or near the satellite's closest approach to Earth, and appears abnormally large and bright as a result. (Image Credit: Jeff Miller - University Communications, University of Wisconsin - Madison)
The full Moon has a reputation for trouble. It raises high tides, it makes dogs howl, it wakes you up in the middle of the night with beams of moonlight stealing through drapes. If a moonbeam wakes you up on the night of November 14th, 2016, you might want to get out of bed and take a look. This full Moon is a "Super Moon," and is as much as 14 percent bigger and 30 percent brighter than other full Moons of 2016.
The scientific term for the phenomenon is "Perigee Moon." Full Moons vary in size because of the oval shape of the Moon's orbit. The Moon follows an elliptical path around Earth with one side (perigee) about 50,000 km closer than the other (apogee). Full Moons that occur on the perigee side of the Moon's orbit seem extra big and bright. Such will be the case on November 14, 2016, when the Moon reaches perigee.
Okay, the Moon appears 14 percent bigger than usual, but can you really tell the difference? It's tricky -- There are no rulers floating in the sky to measure lunar diameters. Hanging high overhead with no reference points to provide a sense of scale, one full Moon can seem much like any other.
The best time to look is when the Moon is near the horizon. For reasons not fully understood by astronomers or psychologists, low-hanging Moons look unnaturally large when they beam through trees, buildings, and other foreground objects.
Folklore holds that all kinds of wacky things happen under the light of a full Moon. Supposedly, hospital admissions increase, the crime rate ticks upward, and people behave strangely. The idea that the full Moon causes mental disorders was widespread in the Middle Ages. Even the word "lunacy," meaning "insanity," comes from the Latin word for "Moon."
The majority of modern studies, however, show no correlation between the phase of the Moon and the incidence of crime, sickness, or human behavior. The truth is, the Moon is less influential than folklore would have us believe.
It's true that a perigee full Moon brings with it extra-high "perigean tides," but according to the National Oceanic and Atmospheric Administration (NOAA) this is nothing to worry about. In most places, lunar gravity at perigee pulls tide waters only a few centimeters (an inch or so) higher than usual. Local geography can amplify the effect to about 15 centimeters (six inches) -- not exactly a great flood.
Super perigee Moons are actually fairly common. The Moon becomes full within a few hours of its closest approach to Earth about once a year on average.
Nevertheless, there is something particularly noteworthy about this month's Super Moon. During the moment of perigee, the centers of the Earth and Moon will be only 221,524 miles apart. That is the closest approach of the Moon to the Earth in over 68 years. Moreover, there will not be a closer one for another 18 years.
During the last closer perigee, on January 26, 1948, the Earth and Moon were separated by only 221,495 miles. They were just 29 miles closer together. The next time the perigee is closer than this month's will be on November 25, 2034, when they will be only 221,486 miles apart -- 39 miles closer together than they will be this month. Both of those occasions qualify as Super Moons.
On November 14, the Moon is at perigee at 6:21 AM EST. The Full Moon occurs at 8:52 AM EST -- just an hour and a half later. Incidentally, the Moon at that moment will have set below the horizon for most of the United States. Only on the West Coast will it still be above the horizon.