The full moons which are supermoons occur when the Moon and Earth are less than 361863 kilometers (224851 miles) apart. A supermoon is the coincidence of a full moon or a new moon with the closest approach the Moon makes to the Earth on its elliptical orbit, resulting in the largest 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 such as earthquakes and volcanic eruptions. This has proven to be true many times. A thumbs up for the validity of astrology! Astrologer Rick Nolle coined this term, it appeared in Dell Horoscope magazine in 1979. Rick is a brilliant astrologer whom I once had the privilege to meet briefly before he moved from Florida out of state.
The opposite phenomenon, an apogee-syzygy, has been called a micromoon,though this term is not as widespread as supermoon.
The Moon’s distance varies each month between approximately 357,000 kilometers (222,000 mi) and 406,000 km (252,000 mi) due to its elliptical orbit around the Earth (distances given are center-to-center).
According to NASA, a full moon at perigee is up to 14% larger and 30% brighter than one at its farthest point, or apogee.
The name “supermoon” was coined by astrologer Richard Nolle in 1979, arbitrarily defined as:
…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.
Nolle described that the moon causes “geophysical stress” during the time of a supermoon. He predicted a major hurricane at the time he coined the word, this did indeed occur and it coincided with a supermoon.
The term supermoon is not used within the astronomical community, which use the term perigee-syzygy or perigee full/new moon. Perigee is the point at which the Moon is closest in its orbit to the Earth, and syzygy is a full or new moon, when the Earth, the Moon and the Sun aligned. Hence, a supermoon can be regarded as a combination of the two, although they do not perfectly coincide each time.
The full moon was grinning…honestly on July 12th…a beautiful night…and sky….enjoyed the article ….thank you
Smiles, I am glad you were pleased, Sherry Joy. Another Supermoon in August …