The day of the closest SuperMoon in 2012 (May 5 or May 6, depending on location), arrived with less fanfare than the March 19, 2010, SuperMoon: an astronomical event that, according to many in 2011, only occurs once every 18 years. How is it possible that a SuperMoon was in the sky above only a little over a year later? The answer lies in the hype that surrounded the March 2011, full moon. Hype that was mostly inaccurate, exaggerated, or downplayed information, tossed about like a salad. This misrepresentation of the facts caused undue fear and anxiety as well as awe. It did nothing for the understanding of what was really happening.
What exactly is a “SuperMoon”?
Astrologer Richard Nolle of Astropro.com coined the term SuperMoon in 1979, to describe with ease two celestial events, as seen from earth, that occur at the same time, technically called perigee-syzygy in the astronomical community.
Perigee is when the moon is at its closest distance to earth in a given orbit (month). Apogee is the opposite.
When Earth, the Sun and the moon align, a syzygy is occurring. When the earth is in the middle, it is a full moon because the Sun is illuminating the surface of the moon that is perceivable. When the moon is in the middle, it is a new moon and the sun is illuminating the surface of the moon that is not visible to observers on earth.
A SuperMoon happens when the full or new moon occurs at the same time the moon is at 90% or greater of its mean closest approach to earth. On May 5/6, 2012, this distance was 356,955 km.
An extreme SuperMoon is a SuperMoon or perigee-syzygy that is extremely close to earth, at 100% or greater of its mean perigee. This was the case in March of 2011, when the Moon was only 356,575 km away from Earth.
Although the Moon appears bigger and brighter to observers on Earth during a perigee-syzygy, it is not. The Moon is simply closer to Earth, appearing larger and more dazzling than normally observed. Dr. James Garvin, chief scientist at NASA’s Goddard Space Flight Center estimates the Moon at these times could appear as much as 14% bigger and 30% brighter than regular full moons.
It is interesting to note that from March 1901 to December 1, 2100, extreme SuperMoons only occur twice when the Moon is new, both in the 21st Century.
How often do SuperMoons actually occur?
Perigee-syzygies occur quite often throughout the year, from as little as three times to at most six times, according to the table published by Richard Nolle in his article “21st Century SuperMoon Alignments”. The years 2002 to 2013 will see 57 perigee-syzygies, with four of these SuperMoons considered extreme SuperMoons. The next extreme SuperMoon will be on November 13/14, 2016.
2002-5 2008-5-X
2003-5 2009-5
2004-3 2010-5-X
2005-4-X 2011-6-X
2006-5 2012-5
2007-6 2013-3
It is clear by the data that SuperMoons are not rare nor do they only happen every 18 years. The data also holds the same conclusion concerning extreme SuperMoons. The dates for the last three perigee-syzygies of 2012 are as follow:
• June 3/4, full moon, perigee of 358,482km
• November 13/14, new moon, perigee of 357,360km
• December 12/13, new moon, perigee of 357, 073km
What effect do SuperMoons have on Earth?
Spring tides occur twice a month during full and new moons. Due to the alignment, the Sun is exerting a gravitational pull on Earth in combination with the Moon. With the Sun’s gravitational force only 46% as strong as the Moon’s pull, it nevertheless affects the height of the ocean’s tides. The tides will climb especially high and then fall to lower than low tides in the same day. Spring tides are higher than neap tides that occur when the Moon is in either of its quarter phases. At these times, the Sun and Moon are at right angles to each other, cancelling out each other’s tidal influences.
Fundyforce.ca says:
“…The greatest tidal range and fastest water speeds occur during “perigean spring tides.”… During perigean tides, the Moon, in its elliptical orbit, is nearest Earth (“perigee”) and the lunar tide is greatest. “
Perigean spring tides are the tides under a perigee-syzygy, a SuperMoon. These tides are said to precipitate seismic and meteorological happenings on a greater scale than normal. However, Dr. James Garvin has this to say:
“The effects on Earth from a supermoon are minor, and according to the most detailed studies by terrestrial seismologists and volcanologists, the combination of the moon being at its closest to Earth in its orbit, and being in its ‘full moon’ configuration (relative to the Earth and sun), should not affect the internal energy balance of the Earth since there are lunar tides every day….”
The SuperMoons are mesmerizing and it is evident that another one will “appear” soon enough. As for the calamitous affect this Moon has on the spring tides, if there are any worrying over the potential damages to Earth and its inhabitants, further research regarding tidal, seismic, volcanic and meteorological history during these astronomical events should be undertaken to garner a better understanding.
