The moon last night was absolutely mesmerizing ... I'm not sure what a super moon is ... I guess I could look into it, but ... I prefer at times to wrap myself in ignorance like a thick dark woolen cloak.
What Would Nostradamus Do? (WWND) ...
Sorry soliver, I can't seem to leave well enough alone. A supermoon was not really mentioned until recent years, but the opposite is a micromoon, and although this happens just as often, It does not sound very exciting so we don't seem to get the hype on those.
Any full moon is mesmerizing to me, and draws my attention without fail.
So here's the definition of a "supermoon"
A supermoon is a full moon or a new moon that approximately coincides with the closest distance that the Moon reaches to Earth in its elliptic orbit, resulting in a larger-than-usual apparent size of the lunar disk as seen from Earth.The technical name is the perigee syzygy of the Earth–Moon–Sun system. The term supermoon is not astronomical, but originated in modern astrology. The association of the Moon with both oceanic and crustal tides has led to claims that the supermoon phenomenon may be associated with increased risk of events like earthquakes and volcanic eruptions, but there is no evidence of such a link
The opposite phenomenon, an apogee syzygy, has been called a micromoon, though this term is not as widespread as supermoon.
The most recent supermoon occurrence was on December 3, 2017 The one on November 14, 2016 was the closest supermoon since January 26, 1948, and will not be surpassed until November 25, 2034. The closest supermoon of the century will occur on December 6, 2052.
Occasionally, a supermoon coincides with a total lunar eclipse. The most recent occurrence of this was in September 2015, while the next one will be in October 2033.
The supermoon of March 19, 2011 (right), compared to a more average moon of December 20, 2010 (left), as viewed from Earth
The Moon's distance varies each month between approximately 357,000 and 406,000 kilometers (222,000 and 252,000 mi) because of its elliptical orbit around the Earth(distances given are centre-to-centre).
A full moon at perigee is visually larger up to 14% in diameter than at apogee. While the moon's surface luminance remains the same, because of its larger size the illuminance is up to 30% brighter than one at its farthest point, or apogee. While a typical summer full moon at temperate latitudes provides only about 0.05-0.1 lux, a supermoon directly overhead in the tropics could provide up to 0.36 lux.
The supermoon over the Dutch Caribbean, 50 miles (80 km) north of Venezuela, November 15, 2016
The name supermoon was coined by astrologer Richard Nolle in 1979
Nolle also claimed that the moon causes "geophysical stress" during the time of a supermoon. Nolle never outlined why he chose 90%.
... a new or full moon which occurs with the Moon at or near (within 90% of) its closest approach to Earth in a given orbit (perigee). In short, Earth, Moon and Sun are all in a line, with Moon in its nearest approach to Earth.
The term perigee-syzygy or perigee full/new moon is preferred in the scientific community. Perigee is the point at which the Moon is closest in its orbit to the Earth, and syzygyis when the Earth, the Moon and the Sun are aligned, which happens at every full or new moon. Hence, a supermoon can be regarded as a combination of the two, although they do not perfectly coincide each time.
Supermoons will be the marked points nearest the bottom of the graph.
FrequencyBecause synodic and anomalistic months differ by almost two days, perigee and full moon alignments will drift relative to one another. The beat period between the two is about 13.9443 synodic months (about 411.8 days). Thus approximately every 14th full moon will be a supermoon. However, halfway through the cycle the full moon will be close to apogee, and the new moons immediately before and after can be supermoons. Depending on the interpretation of the definition there may be between three and six supermoons per cycle.
Since 13.9443 differs from 14 by very close to 1⁄18, the supermoons themselves will vary with a period of about 18 cycles (about 251 synodic months or 20.3 years). Thus for about a decade the largest supermoons will be full, and for the next decade the largest supermoons will be new.
Effect on tides
The combined effect of the Sun and Moon on the Earth's oceans, the tide, is greatest when the Moon is either new or full. At a lunar perigee, the tidal force is somewhat stronger, resulting in perigean spring tides. But, even at its most powerful, this force is still relatively weak, causing tidal differences of inches at most.
As the tidal force follows an inverse-cube law, that force is 19% greater than average. However, because the actual amplitude of tides varies around the world, this may not translate into a direct effect.
No evidence has been found of any correlation between supermoons with major earthquakes. Regardless of the evidence, there has been media speculation that natural disasters, such as the 2011 Tōhoku earthquake and tsunami and the 2004 Indian Ocean earthquake and tsunami, are causally linked with the 1–2 week period surrounding a supermoon. A large, 7.5 magnitude earthquake centred 15 km north-east of Culverden, New Zealand at 00:03 NZDT on November 14, 2016, also coincided with a supermoon.
Edited by Skywatcher, 03 December 2017 - 05:18 PM.