Close Approach by the Moon to the Earth

Close Approach by the Moon to the Earth

In astrology, a supermoon is a full or new moon that coincides with a close approach by the Moon to the Earth.

The Moon's distance varies each month between approximately 354,000 km (220,000 mi) and 410,000 km (254,000 mi).

The term supermoon was coined by astrologer Richard Nolle in 1979, 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.”

The term supermoon is not widely accepted or used within the astronomy or scientific community, who prefer the term perigee-syzygy.

The combined effect of the Sun and Moon on Earth's oceans, the tide, is greatest when the Moon is new or full. Full Moons during lunar perigees (such as in the case of supermoons) exert an even stronger tidal force, resulting in more extreme high and low tides, but even at their most powerful this force is still considerably weak.

Supermoons & Natural Disasters

Speculations of a link between the occurrence of supermoons and natural disasters such as earthquakes and tsunami are extremely tenuous.

Arguments have been made that natural disasters coinciding with years in which supermoons occurred were influenced by the Moon's increased gravitational strength, though because of the monthly alternation between lunar apogee and perigee such an argument cannot be supported unless the disaster in question falls on the actual date of the supermoon.

It has been argued that the Indian Ocean tsunami and earthquake on December 26, 2004, was influenced by a supermoon which occurred 2 weeks later on January 10, 2005.

However two weeks before a supermoon the Moon is at the opposite point in its orbit: its apogee (greatest distance). Thus a supermoon effect is impossible.

Most recently, astrologers argued that the Tōhoku earthquake and tsunami that hit Japan on March 11, 2011, was influenced by the March 19 supermoon, the closest supermoon since 1992.

The problem with this claim is that on March 11 the Moon was actually closer to apogee than perigee, at approximately 400,000 km (240,000 mi) from the Earth, which is further than the average distance between the Moon and the Earth throughout the Moon's orbital cycle.

While some studies have reported a weak correlation between shallow, very low intensity earthquakes and lunar activity, there is no empirical evidence of any correlation with major earthquakes.

There are approximately 4-6 supermoons annually.
This list displays the upcoming predicted extreme supermoons:
  • March 19, 2011
  • November 14, 2016
  • January 2, 2018
  • January 21, 2023
  • November 25, 2034
  • January 13, 2036