{"id":19340,"date":"2021-06-24T07:42:31","date_gmt":"2021-06-24T07:42:31","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=60075"},"modified":"2021-06-24T07:42:31","modified_gmt":"2021-06-24T07:42:31","slug":"what-is-a-supermoon-and-when-is-the-next-one","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/what-is-a-supermoon-and-when-is-the-next-one\/","title":{"rendered":"What is a supermoon and when is the next one?"},"content":{"rendered":"

\"A <\/p>\n

Tonight\u2019s full Moon, 24 June 2021, will be the last so-called \u2018supermoon\u2019 of the year, designated a \u2018<\/strong>Super Strawberry Moon\u2019. But what is a supermoon, when do they occur, and are they really something to get excited about?<\/p>\n

Supermoons occur at perigee: the point in the Moon\u2019s orbit where it\u2019s closest to Earth. A perigee full Moon appears a little brighter and larger than an average full Moon, and is known by some as a \u2018supermoon\u2019.<\/p>\n

Generally speaking, however, astronomers don\u2019t tend to use these terms (likely a result of the term supermoon\u2019s astrological origins), and the technical name for a \u2018supermoon\u2019 is a perigee syzygy Moon.<\/p>\n

\u00a0<\/p>\n

\"Supermoon<\/div>\n
<\/i> Supermoon Over Central Illinois, 1 January 2018, by Joshua Rhoades. Equipment: Canon EOS 6D DSLR camera, Sigma 100-400mm lens. Credit: Joshua Rhoades<\/span><\/figcaption><\/span><\/div>\n

What is a supermoon and when do they occur?<\/strong><\/h1>\n

A supermoon happens when a full Moon coincides with the Moon\u2019s closest approach to Earth along its orbit.<\/p>\n

We get 12 or 13 full Moons each year but, due to the orientation of the Moon\u2019s orbit, not every full Moon is a supermoon, in the same way that not every full Moon is a lunar eclipse<\/a>.<\/p>\n

The Moon\u2019s orbit around Earth<\/strong><\/h1>\n

The Moon takes just over 27 days to orbit Earth on an elliptical path that takes it from its most distant point from Earth at apogee, to its closest approach at perigee.<\/p>\n

These distances can vary between 406,712km (apogee) and 356,445km (perigee).<\/p>\n

It also takes just over 29 days to cycle from one full Moon to the next, which you can see for yourself if you note the phases of the Moon<\/a> night after night.<\/p>\n

Meanwhile, Earth\u2019s orbit around the Sun<\/a> takes 365 days and this means it takes 14 lunar cycles (411 days) to go from one full perigee Moon to the next one.<\/p>\n

\"Going<\/div>\n
<\/i> Comparison between the perigee (closest) and apogee (farthest) Moons. Credit: Alamy Stock Photo<\/span><\/figcaption><\/span><\/div>\n

When does a supermoon happen?<\/strong><\/h1>\n

The term supermoon refers to both perigee full and new Moons but, as the new Moon is not visible we will concentrate on the full supermoon.<\/p>\n

The name \u2018supermoon\u2019 was first coined by astrologer Richard Nolle in 1979. He defined it as \u201ca new or full Moon that occurs when the Moon is at or near (within 90% of) its closest approach to Earth in its orbit\u201d.<\/p>\n

\"Supermoon<\/div>\n
<\/i> Supermoon engulfed by clouds in Clacton-On-Sea, Essex, UK, captured by Shantelle Robinson with an Olympus E-420. Credit: Shantelle Robinson<\/span><\/figcaption><\/span><\/div>\n

Astronomers prefer the more precise, though perhaps less catchy, term of a perigee full Moon to describe a full Moon that occurs when the Moon\u2019s centre is less than 360,000km from the centre of Earth.<\/p>\n

Or a perigee syzygy full Moon, where syzygy refers to a straight-line configuration of three or more celestial bodies in a gravitational system (in this case Earth, the Moon and the Sun).<\/p>\n

The opposite phenomenon, an apogee syzygy full Moon, is similarly dubbed a \u2018micromoon\u2019.<\/p>\n

\"The<\/div>\n
<\/i> The difference in apparent size between apogee and perigee full Moons.<\/span><\/figcaption><\/span><\/div>\n

\u00a0<\/p>\n

Is a supermoon really much bigger?<\/strong><\/h1>\n

Much has been written about supermoons \u2018stunning\u2019 and \u2018dazzling\u2019 observers, and this is another reason some astronomers balk at the term.<\/p>\n

In reality, a full Moon at perigee appears only 14% <\/span>larger due to being closer to us, and only 30% brighter than an apogee full Moon.<\/p>\n

A supermoon is also only about 7% larger and 15% brighter than an average full Moon.<\/span><\/p>\n

\"A<\/div>\n
<\/i> A perigee full Moon (left) appears 30% brighter and 14% larger than an apogee full Moon (right). Credit: Pete Lawrence<\/span><\/figcaption><\/span><\/div>\n

Without a side-by-<\/span> side comparison, it is difficult to spot the difference from one month to the next, but it is possible to record changes in the Moon\u2019s size<\/a> through photography.<\/p>\n

The difference in brightness is due to the reflected light from the lunar surface that reaches Earth being inversely proportional <\/span>to the square of the distance between them.<\/p>\n

The Moon illusion<\/strong><\/h1>\n

Claims that the Moon appears larger than this are likely to be due to the \u2018Moon illusion\u2019. Indeed, the Moon does appear much larger when observed near the horizon at moonrise and moonset.<\/p>\n

The reason for this optical illusion is still under debate, but is likely to do with the way our brains process objects close to the horizon as being larger when in proximity to buildings and trees, than when they are high in the sky with nothing to compare sizes against.<\/p>\n

\"A<\/div>\n
<\/i> A Boeing 737 silhouetted against the Supermoon of 14 November 2016, captured by Richard Matthews from Staffordshire, UK. Credit: Richard Matthews.<\/span><\/figcaption><\/span><\/div>\n

Do supermoons always come in threes?<\/strong><\/h1>\n

April 2021 brought the first of three consecutive supermoons in 2021, but this is not unusual.<\/p>\n

Indeed, every 14 lunar months the series of full Moons cycles from largest to smallest and back again as the Moon orbits Earth.\u00a0Perigee can last between two and five full Moons.<\/p>\n

For a full Moon to be classed as \u2018super\u2019 it must occur when it is around 360,000km away from Earth or less, so the full Moons occurring either side commonly also fall within the supermoon category.<\/span><\/p>\n

On rare occasions<\/span> we get two or four supermoons in a row, but three is the most common.<\/p>\n

Gallery: 7-8 April 2020 supermoon<\/strong><\/h1>\n
<\/i> <\/p>\n
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\"Elliot<\/div>
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Elliot Hepplewhite (aged 16), Cheshire, UK. Equipment: iPhone 6, Meade ETX-90 telescope.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"S\u00e9rgio<\/div>
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S\u00e9rgio Concei\u00e7\u00e3o, Elvas, Portugal. Equipment: Nikon D5100 DSLR, 190mm lens.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Peter<\/div>
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Peter Lewis, London, UK. Equipment: Samsung phone camera, 8-inch Dobsonian.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Daniel<\/div>
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Daniel Tackley, Manchester, UK. Equipment: Canon EOS 5D MkIII DSLR camera, Sigma 60-600mm lens.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Nick<\/div>
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Nick Williams, NE London, UK. Equipment: Canon EOS 90D DSLR camera, 70-300mm lens.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Steve<\/div>
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Steve Walker, Kent, UK. Equipment: Nikon D3200 DSLR camera, tripod.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Graeme<\/div>
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Graeme Whippy, Essex, UK. Equipment: Nikon D5300 DSLR camera, 55-300mm lens.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"John<\/div>
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John Pow, Kirkcaldy, UK. Equipment: Nikon D810, 600mm lens (10-shot stack)<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Sonia<\/div>
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Sonia Bashir, Lancashire, UK. Equipment: Canon EOS 5D MkIV DSLR camera, Canon EF 100-400mm lens.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Alan<\/div>
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Alan Irvine, Lanzarote, Spain. Equipment: HTC mobile phone camera<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Steve<\/div>
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Steve Brown, North Yorkshire, UK. Equipment: Canon EOS 250D DSLR camera, 300mm lens, static tripod<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Roger<\/div>
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Roger Hutchinson, London, UK. Equipment: Canon EOS 6D DSLR camera, Canon EF 70-300mm lens.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"James<\/div>
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James West, Eastleigh, UK. Equipment: Canon EOS 90D DSLR camera, Sigma 150-600mm sport lens.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Mark<\/div>
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Mark Macleod, Fife, UK. Equipment: Panasonic bridge camera, Manfrotto mini tripod.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Anthony<\/div>
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Anthony Ward, Anglesey, UK. Equipment: Canon EOS 7D DSLR camera, 400mm lens.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Jon<\/div>
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Jon Sharpe, West Yorkshire, UK. Equipment: Canon EOS 800D DSLR camera, RedCat 51 refractor.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Andrew<\/div>
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Andrew Birbeck, north Norfolk. Equipment: Samsung Galaxy phone, Celestron Nexstar 5SE, Celestron NexYZ smartphone adapter<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"David<\/div>
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David Queenan, Carriden Church Tower, Bo\u2019ness, UK. Equipment: Fujifilm X-T3 camera, XF50-140mm lens, 1.4x teleconverter<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Simon<\/div>
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Simon Jones, Hampshire, UK. Equipment: Canon EOS 7D MarkII DSLR camera, 100-400 L lens.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Robert<\/div>
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Robert Thomas, Hampshire, UK. Equipment: Huawei P30 Pro phone (night mode)<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n
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\"Andile<\/div>
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Andile Dlodlo, Johannesburg, South Africa. Equipment: Canon EOS 4000D DSLR camera.<\/span> <\/figcaption> <\/i> <\/span>\n<\/div>\n<\/figcaption><\/figure>\n<\/div><\/div>\n<\/div>\n<\/div>\n

Effects of a supermoon<\/strong><\/h1>\n

Many people talk about the effects of a supermoon on us and our planet, but there is scant scientific evidence to support claims that supermoons cause earthquakes, volcanic eruptions, extreme weather and tsunamis, or floods and pestilence!<\/p>\n

The Moon is, of course, the driving force for Earth\u2019s tides: full and new Moons are when the Earth, Sun and Moon line up to produce extreme spring tides, but the effect of perigean spring tides only increases the tidal variations by about 5cm on average.<\/p>\n

\"Supermoons<\/div>\n
<\/i> Supermoons have little added influence on Earth\u2019s tides. Credit: Jeff Morgan \/ Getty Images<\/span><\/figcaption><\/span><\/div>\n

In recent years there have indeed been a handful of tsunamis and earthquakes that coincided with a supermoon but, with around three supermoons <\/span>every 14 months it would be unusual if such a disaster did not coincide with a supermoon now and then.<\/p>\n

A supermoon may not be so \u2018super\u2019, or even rare, but once you cut through the hype, it is still a great way to engage with our nearest celestial neighbour. For more on lunar-gazing, read our guide on how to observe the Moon<\/a>.<\/p>\n

Jenny Winder is a freelance science writer, astronomer and broadcaster.<\/strong><\/em><\/p>\n

This guide originally appeared in the April 2021 issue of BBC Sky at Night Magazine.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Tonight\u2019s full Moon, 24 June 2021, will be the last so-called \u2018supermoon\u2019 of the year, designated a \u2018Super Strawberry Moon\u2019. But what is a supermoon, when do they occur, and are they really something to get excited about? Supermoons occur at perigee: the point in the Moon\u2019s orbit where it\u2019s closest to Earth. A perigee […]<\/p>\n","protected":false},"author":24,"featured_media":0,"template":"","categories":[1],"acf":{"readingTimeMinutes":"9"},"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"Tonight\u2019s full Moon, 24 June 2021, will be the last so-called \u2018supermoon\u2019 of the year, designated a \u2018Super Strawberry Moon\u2019. But what is a supermoon, when do they occur, and are they really something to get excited about? Supermoons occur at perigee: the point in the Moon\u2019s orbit where it\u2019s closest to Earth. A perigee…","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/19340"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=19340"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=19340"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}