Supermoon

A juxtaposition of the apparent diameters of a more-average full moon on December 20, 2010 (left), and of the supermoon of March 19, 2011 (right) as viewed from Earth

A supermoon is a full moon or a new moon that nearly coincides with perigee—the closest that the Moon comes to the Earth in its orbit—resulting in a slightly larger-than-usual apparent size of the lunarTemplate:Nbspdisk as viewed from Earth.Template:Zwj The technical name is a perigee syzygy (of the Earth–Moon–Sun system) or a full (orTemplate:Nbspnew) Moon around perigee.Template:ZwjTemplate:Efn Because the term supermoon is astrological in origin, it has no precise astronomical definition.Template:Zwj

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 no such link has been found.Template:Zwj

The opposite phenomenon, an apogee syzygy or a full (orTemplate:Nbspnew) Moon around apogee, has been called a micromoon.Template:Zwj

Definitions

The name supermoon was coined by astrologer Richard Nolle inTemplate:Nbsp1979, in [[Dell Horoscope|DellTemplate:NbspHoroscope]] magazine arbitrarily defined as: Template:Blockquote

NASA image showing comparison of a supermoon (left) and a micromoon (right)

He came up with the name while reading Strategic Role Of Perigean Spring Tides in Nautical History and Coastal Flooding, published inTemplate:Nbsp1976 by FergusTemplate:NbspWood, a hydrologist withTemplate:NbspNOAA.Template:ZwjTemplate:Zwj Nolle explained inTemplate:Nbsp2011 that he based calculations on 90% of the difference in lunar apsis extremes for the [[solar year|solarTemplate:Nbspyear]]. In other words, a full or newTemplate:Nbspmoon is considered a supermoon if $l{d}_s\le l{d}_p+0.1\ast (l{d}_a-l{d}_p)$, where $l{d}_s$ is the lunar distance at syzygy, $l{d}_a$ is the lunar distance at the greatest apogee of the year, and $l{d}_p$ is the lunar distance at the smallest perigee of the year.Template:ZwjTemplate:Zwj

In practice, there is no official or even consistent definition of how near perigee the fullTemplate:NbspMoon must occur to receive the supermoon label, and newTemplate:Nbspmoons rarely receive a supermoon label. Different sources give different definitions.Template:ZwjTemplate:Zwj

The term perigee-syzygy or perigee fullTemplate:Wbr/Template:WbrnewTemplate:Nbspmoon is preferred in the scientific community.Template:Zwj Perigee is the point at which the Moon is closest in its orbit to the Earth, and syzygy is when the Earth, the Moon and the Sun are aligned, which happens at every full or [[new moon|newTemplate:Nbspmoon]]. Template:Shy [[Fred Espenak|FredTemplate:NbspEspenak]] uses Nolle's definition but preferring the label of fullTemplate:NbspMoon at perigee, and using the apogee and perigee nearest in time rather than the greatest and least of the year.Template:Zwj WoodTemplate:Nbspused the definition of a full or new moon occurring within 24Template:Nbsphours of perigee and also used the label perigee-syzygy.Template:Zwj

Wood also coined the less-used term proxigee where perigee and the full or newTemplate:Nbspmoon are separated by 10Template:Nbsphours or less.Template:Zwj Nolle has also added the concept of extreme supermoon inTemplate:Nbsp2000 describing the concept as any new or fullTemplate:Nbspmoons that are at "100% or greater of the meanTemplate:Nbspperigee".Template:Zwj

Occurrence

Of the possible 12 or 13 full (orTemplate:Nbspnew) moons each year, usually three or four may be classified as supermoons, as commonly defined.

The full moon occurred Thursday December 4, 2025 at 3:14 PST, following an occurrence on November 5, 2025. Due to the event occurring in December it is usually called the "cold moon". The full moon rises on the 4th and 5th of December, Thursday and Friday Evening.

The supermoon of November 14, 2016, was the closest full occurrence since JanuaryTemplate:Nbsp26, 1948, and will not be surpassed until NovemberTemplate:Nbsp25, 2034.Template:Zwj

The closest full supermoon of the 21stTemplate:Nbspcentury will occur on DecemberTemplate:Nbsp6, 2052.Template:Zwj

Supermoons will be the marked points nearest the bottom of the graph.

The oscillating nature of the distance to the full or new moon is due to the difference between the [[synodic month|synodicTemplate:Nbspmonth]]Template:ZwjTemplate:Efn and [[anomalistic month|anomalisticTemplate:Nbspmonth]]s.Template:ZwjTemplate:ZwjTemplate:Efn The period of this oscillation is about 14Template:Nbspsynodic months, which is close to 15Template:Nbspanomalistic months. Thus every 14Template:Nbsplunations there is a fullTemplate:Nbspmoon nearest to perigee.

Occasionally, a supermoon coincides with a total lunar eclipse. The most recent occurrence of this by any definition was in [[May 2022 lunar eclipse|MayTemplate:Nbsp2022]], and the next occurrence will be in [[October 2033 lunar eclipse|OctoberTemplate:Nbsp2033]].Template:ZwjTemplate:Update after

In the Islamic calendar (a lunar calendar), the occurrence of full supermoons follows a Template:Nowr cycle. In the firstTemplate:Nbspyear, the fullTemplate:Nbspmoon is near perigee in monthTemplate:Nbsp1 or 2, the next year in monthTemplate:Nbsp3 or 4, and so on. In the seventhTemplate:Nbspyear of the cycle the fullTemplate:Nbspmoons are never very near to perigee. Approximately every 20Template:Nbspyears the occurrences move to oneTemplate:Nbspmonth earlier. Template:As of such a transition is occurring, so fullTemplate:Nbspsupermoons occur twice in succession. For example in [[Hijri year|Template:Langr year]]Template:Nbsp1446, they occur both in monthTemplate:Nbsp3 (Template:Itco, on SeptemberTemplate:Nbsp18, 2024) and in monthTemplate:Nbsp4 (Template:Itco, on OctoberTemplate:Nbsp17, 2024).

Appearance

The supermoon of March 19, 2011 (right), compared to an average full moon of January 18, 2011 (left), as viewed from Earth

A full moon at perigee appears roughly 14%Template:Nbsplarger in diameter than at apogee.Template:Zwj Many observers insist that the Moon looks bigger to them. This is likely due to observations shortly after sunset when the Moon appears near the horizon and the [[Moon illusion|MoonTemplate:Nbspillusion]] is at its most apparent.Template:Zwj

While the Moon's surface luminance remains the same, because it is closer to the Earth the [[illuminance|Template:Em]] is about 30%Template:Nbspbrighter than at its farthest point, or apogee. This is due to the [[inverse square law|inverse squareTemplate:Nbsplaw]] of light, which changes the amount of light received on Earth in inverse proportion to the distance from the Moon. But, the perceived brightness will be the same; the Moon will just be smaller in one's field of view. That change in size is exactly proportional to the change in the amount of light.Template:Zwj A supermoon directly overhead could provide up to Template:Val.Template:Zwj

Effects on Earth

Claims that supermoons can cause natural disasters, and the claim of Nolle that supermoons cause "geophysical stress", have been refuted by scientists.Template:ZwjTemplate:ZwjTemplate:ZwjTemplate:Zwj

Despite lack of scientific evidence, there has been media speculation that natural disasters, such as the [[2011 Tōhoku earthquake and tsunami|2011Template:NbspTemplate:Langr earthquake and tsunami]] and the [[2004 Indian Ocean earthquake and tsunami|Template:Nowr earthquake and tsunami]], are causally linked with the Template:Nowr period surrounding a supermoon.Template:Zwj The Template:Nowr [[2016 Kaikōura earthquake|2016Template:NbspTemplate:Langr earthquake]] in NewTemplate:NbspZealand also coincided with a supermoon.Template:ZwjTemplate:Zwj Tehran earthquake on MayTemplate:Nbsp8, 2020, also coincided with a supermoon.

Scientists have confirmed that the combined effect of the Sun and Moon on the Earth's oceans, the tide,Template:Zwj is greatest when the Moon is either new or full.Template:Zwj and that during lunar perigee, the tidal force is somewhat stronger,Template:Zwj resulting in perigean spring tides. While this increased tidal force is relatively weakTemplate:ZwjTemplate:ZwjTemplate:ZwjTemplate:Efn in a global geophysical context, it can induce measurable local effects. For example, research based on 25Template:Nbspyears of daily observations on a sandy beach has shown that the larger tidal ranges produced by supermoons, known as [[king tide|kingTemplate:Nbsptide]]s, make beach erosion in the upper [[swash zone|swashTemplate:Nbspzone]] more likely.Template:Zwj These Template:Nowr data indicate that beach morphology fluctuates in cycles related to the supermoon, and that erosion during highTemplate:Nbspwaves can be more severe when coincident with a supermoon.

Super Blood Moon

A Super Blood Moon on September 27, 2015

Total lunar eclipses which fall on supermoon and micromoon days are relatively rare. In the 21stTemplate:Nbspcentury, there are 87Template:Nbsptotal lunar eclipses, of which 28 are supermoons and 6 are micromoons. Almost all total lunar eclipses in [[Lunar Saros 129|Lunar SarosTemplate:Nbsp129]] are micromoon eclipses.

The Super Blood Moon is an astronomical event that combines two phenomena: a supermoon and a total lunar eclipse, resulting in a larger, brighter, and reddish-colored Moon. A total lunar eclipse takes place when the Earth aligns between the Sun and the Moon, causing Earth's shadow to fall on the Moon. As the shadow covers the Moon, sunlight passing through Earth's atmosphere scatters, filtering out most [[blue|blueTemplate:Nbsplight]] and casting a reddish hue on the Moon. This phenomenon is often called a [[Blood moon (eclipse)|bloodTemplate:Nbspmoon]] because of its striking red or orange color.

When these two events coincide, the Moon appears both larger and redder than usual, leading to the term Super BloodTemplate:NbspMoon. This unique alignment creates a visually impressive and rare sight that has inspired folklore and intrigue for centuries. Super Blood Moons are relatively infrequent, occurring about once every few years, making them a notable event for astronomers and skywatchers alike.

Annular solar eclipses

Annular solar eclipses occur when the Moon's apparent diameter is smaller than the Sun's. Almost all annular solar eclipses between 1880 andTemplate:Nbsp2060 in [[Solar Saros 144|Solar SarosTemplate:Nbsp144]] and almost all annular solar eclipses between 1940 andTemplate:Nbsp2120 in [[Solar Saros 128|Solar SarosTemplate:Nbsp128]] are micromoon annular solar eclipses.Template:Zwj

See also

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External links

• Lunar Apogee/Perigee Calculator at Fourmilab
• Richard Nolle's definition
• Richard Nolle's list of supermoons in the 21stTemplate:Nbspcentury
• Full Moon at Perigee (Super Moon): 2001 to 2100 by [[Fred Espenak|FredTemplate:NbspEspenak]]
• Template:Link with archives
• Supermoons and Micromoons
• Next Supermoons