Supermoon is a phenomenon that the moon is near the perigee when it is a new moon or a full moonnew moon；When the moon is at perigee, it happens to be full moon, which is called superfull moon。[1]As the moon orbits the earth in an elliptical orbit, the distance between the moon and the earth is constantly changing, so the closer the moon is to the earth when the full moon occurs, the larger the full moon will be seen.When the new moon occurs, the moon faces the earth with its dark side and rises and disappears with the sun. It is difficult for people to see it with the naked eye, let alone notice that the super new moon is larger than the ordinary new moon, so the super new moon is rarely mentioned.In some contexts, the super moon refers to the super full moon.
The term "super moon" was first proposed by Richard Nolle, an American astrologer, in 1979. Many mainstream astronomers do not agree with the term "super moon", because from a scientific definition, it is more accurate to call it perigee full moon.When the full moon is in“Perigee”Nearby, it looks bigger and brighter than the normal full moon.At this time, the near point month is about 14% larger than the far point month, and about 30% brighter (depending on the meteorological conditions).However, such changes in size and brightness are not easily perceived by human eyes.
On September 18, 2024, this' super moon 'will be the largest full moon in 2024.[24]The "super moon" and the Mid Autumn full moon almost coincide perfectly, appearing only once every 60 years on average.[25]At 10:35 a.m. on September 18, 2024, we will usher in the roundest "look" month[26]。
When Richard Noel put forward the concept of super moon, he thought that the full moon or new moon is called super moon within 90% of the range closest to the earth.However, since this is not a strict astronomical concept, there is no standard definition for the new moon or full moon within the distance between the moon and the earth.
Another widely accepted definition is that a full moon less than 360000 kilometers from the earth to the moon can be called a "super moon".[1]On the basis of this definition, someone called the full moon with a distance of less than 356500 kilometers between the earth and the moon "super super moon".From this definition, the super moon is not rare. Every year, there will be 4-6 super moons, and the super new moon and the super full moon account for roughly half of each other.
Figure: Diagram of Earth Moon Distance from 2022-2025.The solid line represents the distance between the moon and the earth, the red dot represents the full moon, the red cross represents the new moon, the red dot near the bottom means the super full moon, and the red cross near the bottom means the super new moon
However, the best time to observe the "super moon" is when the moon just rises or sets.At this time, the moon is near the horizon. When the reference object exists, it will appear larger because of the psychological effect.
The super moon will be 30% and 14% larger than the smallest full moon, and 16% and 7% larger than the normal full moon.In fact, on a sunny winter night, people can see the full moon brighter when away from the city lights.However, if observed near the city, it is difficult to distinguish the difference between the super moon and the normal full moon due to the influence of city lights.If clouds or haze exist, there is no brightness difference.
Production principle
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The average distance between the moon and the earth is about 380000 kilometers, but the orbit of the moon around the earth is not circular, but elliptical, and the eccentricity of the ellipse is also changing periodically.According to measurements, when the moon is at perigee, the distance between the moon and the earth is between 3564 and 3704 thousand kilometers, with an average distance of 363 thousand kilometers, while when the moon is at apogee, the average distance is 406 thousand kilometers, with a difference of 10.41%.
The mean elliptical orbit of the moon
When the moon is close to us, we will see a larger moon. When the moon is far away from us, we will see a smaller moon.If the distance difference is not very large, such as tens or hundreds of kilometers, ordinary people will not have a clear feeling, but the perigee and apogee are more than 50000 kilometers apart, there is a relatively obvious difference.
Because the moon is the only satellite of the earth, it operates under the gravity of the earth, and the earth operates under the gravity of the sun, so it is said that when the moon moves to a certain point or any point, it will be affected by the combined gravity of different celestial bodies in space, and this gravity is a very complex system, so the orbit of the moon around the earth is relatively complex,The perigee will always change.
There are two key points for the generation of the "super moon", one is the nearest and the other is the roundest.If the moon happens to run to the perigee or the full moon when it is near the perigee, the moon we see on the earth is 12.5-14.1% larger than when it is at the apogee, we will appreciate the moon which is bigger and brighter than usual, and many people also call it "super moon".
The point in the lunar orbit closest to the earth is called "perigee", and the opposite is "apogee".Every time the moon revolves around the earth, it passes through a perigee and an apogee, once every 27.55455 days on average. This kind of moon passes twice in successionPerigeeThe time interval (or apogee) isPerigee month(27.55455).The two full moons are about 29.53 days apart.Since the perigee time and full moon time of the moon can be accurately calculated each month, their respective operating cycles can be used to calculate when the "super moon" can be seen.
In an operation cycle of the moon moving around the earth, if there is a "super moon", it usually does not appear when the moon is closest to the earth. There will be a time difference between the appearance of the near moon point and the full moon, which may occur within one hour or several hours. The smaller the time difference, the bigger the theoretically seen moon will be.Of course, it's hard to see the difference with the naked eye.
Date of occurrence
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The convergence of the new moon and the star moon
Before calculating the occurrence date of the "super moon", first look at several operation cycles of the moon:
Schematic diagram of lunar cycle
With the surrounding stars as the background, the revolution period of the moon is 27.32 days, which is calledSidereal monthEach time the star, moon and moon will pass the perigee of an elliptical orbit.However, with the reference to the sun earth line, the moon has a cyclical change of 29.53 days, which is calledNew Moon。The main difference between the two is that the former is still short of the distance the earth has traveled in this month.Suppose that the moon starts to revolve between the earth and the sun (the moon phase is the new moon at this time). After 27.32 days, the moon will revolve around the earth. But because the earth also revolves an angle around the sun during this period of time, the moon will have to revolve for another two days or so before it can return to the space between the earth and the sun and return the moon phase to the new moon.That is, the number of days between the phases of two new moons is 29.53 days. Similarly, the two full moons are also 29.53 days apart.The angular velocity difference between the earth's revolution and the moon's revolution determines the period of new moon observation
The Star Moon and the New Moon
according tocalendarAccording to the calculation, 14 new moons are very close to 15 star months.That is to say, every 14 cycles of the moon (that is, 14 "new moons" in astronomy, equivalent to 413.4 days, roughly equivalent to 14 months in the lunar calendar), at the 14th roundest time, the moon passes or approaches the perigee of the 15th sidereal month at about the same time.That is to say, such a "super moon" is welcomed every one year, one month and 18 days, that is, every 413 days.But sometimes, the full moon before and after this calculation will also be near the near moon point. Many people also call this full moon "super moon" these years.
Super Moon and Eclipse - Saro Cycle
The orbital plane of the moon's revolution is called the white track plane, which has an included angle of about 5 ° with the ecliptic plane, which makes the moon's revolution more complex, and cannot be simply summarized with a rough lunar revolution period of 27.32 days as in the previous section.The two intersections of the white and ecliptic are called ascending and descending intersections respectively, and the motion cycle of the moon passing the ascending (or descending) intersection twice is calledNode month。The orientation of the white road surface is not fixed, and it rotates about 20 degrees every year (the cycle is 18.6 years)[3], which makes the intersection of the white path and the ecliptic move continuously.In addition, the perigee period of the moon passing through the elliptical orbit twice is calledPerigee month。The perigee of an elliptical orbit will also precess, so the perigee moon, the intersection moon and the sidereal moon are not equal.According to the measurement, the period of the node month is 27.21222 days, and the period of the near point month is 27.55455 days.
Figure: The orbit of the moon (white) and the earth (yellow) have an included angle of 5 ° | Source: timeanddate
When estimating the period of the super moon, what we are looking for isNew MoonandPerigee monthApproximate least common multiple of
14 × 29.53059=413.428 days
15 × 27.55455=413.318 days
It's two and a half hours behind.If we estimate the period of solar and lunar eclipses, what we are looking for isNew MoonandNode monthApproximation ofLeast common multiple, will get
223 × 29.530588=6585.32157 days
242 × 27.212220=6585.35724 days
Only 50 minutes were left in the middle.This 6585.32 days can be converted into 11.32 days in 18 years, which is calledSaro periodIt corresponds to the cycle of solar and lunar eclipses. A Saro cycle will have 43 solar and 28 lunar eclipses.Coincidentally, it is close to 239 perigee months
239 × 27.55455=6585.54 days
It is only five hours different from the Saro cycle.So if the moon has a super lunar eclipse near the perigee, then after a Sarro cycle, the moon will also approximate to the perigee and have a lunar eclipse.
Previous appearances
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2011
On the evening of March 18, 2011, over Huntington Beach, Los Angeles, the United States, a bright moon had just risen. In the camera lens, a passenger plane just passed the moon.The National Aeronautics and Space Administration (NASA) announced that on March 19, the moon reached the closest position to the earth in 19 years, and its distance from the earth was only 350000 kilometers.In the early morning of March 20, the roundest and largest moon in 2011 appeared in the night sky, and the full moon was seen in sunny areas in China.
The moon over Los Angeles on the evening of March 19, 2011
March 19, 2011, Espejo Castle, Cordoba, Spain
2012
The largest and roundest moon in 2012 (also called "super moon") appeared in the night sky on May 6 (April 16 in the lunar calendar).At 11:35 on May 6, the "super moon" appeared in the sky. The moon reached its full phase and was in the roundest state. At 12:00 at noon, the moon happened to reach the perigee. At this time, the moon was the nearest time to the earth in the year, so the apparent diameter of the moon was the largest, which was also the largest full moon in 2012.
2013
At 19:11 on June 23, 2013 (the 16th day of the fifth lunar month), the moon passed the perigee, 356991km away from the earth, and then 21 minutes later, at 19:32, the full moon (look) came again, which was the largest and roundest moon in 2013, that is, the "super moon".
On May 16 of the lunar calendar, the biggest and roundest super moon in 2013 was ushered in.At 19:12, the distance between the moon and the earth was the nearest in the whole year, and the moon looked the largest.At 19:32, the moon, the earth and the sun were in an approximate straight line, and the moon was the roundest.Some netizens said that when the beauty of heaven and earth reached its peak, it was moving.
Hangzhou Super Moon on June 23, 2013
2014
As one of the most anticipated celestial phenomena in 2014, the largest and roundest super moon of the year appeared at 2:00 a.m. on August 11.According to the calculation, at about 1:42 a.m., the moon is the closest to the earth. It is the time when the moon looks at the moon, and it is the time when the moon is the roundest.It is about 12% larger than the normal moon, and its brightness has also increased.
2014 Super Moon
2015
There were six super moons in 2015, and the super moon that appeared on September 28, 2015 was the closest to the Earth in that year.[2]
On September 28, 2015, the "Super Moon" and the "Mid Autumn Full Moon" met happily.
Super Moon
2017
On December 3, 2017, the earth people watched the "super moon" again.This "super moon" is not only the largest full moon in 2017, but also the eighth full moon in the past 80 years.Taking the "super moon" in November 2016 as an example, the moon was only 357000 kilometers away from the earth, which was the closest to the earth since 1948.Compared with the general full moon, the "super moon" looks significantly larger, and its brightness will be 30% higher.
Astronomers said that the full moon on December 3 is also the last full moon in 2017, and it will be about 14% larger than the smallest full moon on June 9, 2017.[4]
On the evening of December 3, 2017, the world welcomed the "super moon" again.The full moon in December is also called the "cold moon". The "cold moon" in 2017 is closer to the earth than in previous years, 14% larger than usual, and 30% brighter.[5]
2019
There will be three super moons in 2019, on January 21, February 19 and March 21.Among them, the second viewing effect is the best.[6]
At 17:02:43 on February 19, 2019, the "super moon" met the Lantern Festival.[7]
On March 21, 2019, the moon will appear in Tianyu. At 9:43 on March 21, 2019, the moon will be "the roundest".[8]
2020
There will be four "super moons" in 2020, respectively on February 9, March 10, April 8 and May 7, of which the two times on April 8 and March 10 are the annual "largest full moon" and "second largest full moon" respectively.The full moon on March 10 occurred on the 17th day of the lunar calendar, and the roundest moment occurred at 1:48 on the 10th. At 14:30 on the same day, the moon passed the perigee, which was the second time that the moon was close to the earth all year round. At this time, the apparent diameter of the moon was very large.[9]
On April 8, 2020, a super moon appeared in the night sky. The difference between the lunar perigee and the full moon was only 8 hours and 26 minutes, and the Earth was closest to the moon all year round. The public saw that the apparent diameter of the moon was the largest in the year.[10]
2020 Super Moon[2]
2021
On April 27, 2021, the second largest full moon of the year will appear in the night sky, and the interested public in China can watch it from the night of April 27 to the early morning of April 28.[13]
On May 26, 2021, the "super moon+red moon+total lunar eclipse" group appeared.According to astronomers, when the position of the moon, the earth and the sun in the universe is in a straight line, the shadow of the earth blocks the moon, and a lunar eclipse will occur.Coincidentally, this total lunar eclipse is also the largest one of the full moon in 2021, which can be said to be the "super moon" rising with eclipse.[14]
Viewing place: When the sky is clear, most regions of China can watch the lunar eclipse except parts of the northwest, but only the eastern region can see the complete lunar eclipse.
Viewing time: The total eclipse starts at 19:11 Beijing time, ends at 19:25 Beijing time, and ends at 20:52 Beijing time.
On the same day of May 26, the moonrise time of some Chinese cities is (in order): 18:44 in Shanghai, 18:58 in Shenzhen, 19:02 in Guangzhou, 19:04 in Harbin and 19:27 in Beijing.
At about 10:00 Beijing time on May 26, 2021, the moon will reach the closest point to the earth. The distance between the two is only 357311 kilometers. The apparent diameter of the full moon will reach 33.5 jiao min, the largest in the year, which is larger than the apparent diameter of the sun at any time.At 19:14 on May 26, the sun, the earth and the moon formed a straight line, and a total lunar eclipse (look) occurred.At this time, the moon is just at the perigee, and only 9 hours away from the moon's roundest moment, so it is called the super moon, which is the second super moon in 2021.[15]
2022
At 19:52 on June 14, 2022, Beijing time, the first perigee in 2022, the full moon, the super moon, appeared.[16]At 7:23 on June 15, the moon passed the perigee;The "maximum full moon" in 2022 occurs on July 14 (June 16 in the lunar calendar).[17]
In the early morning of July 14, 2022, the largest super moon in 2022 will appear, which can be seen all over China.The best observation time is from the evening of July 13 to the early morning of July 14.The super moon (full moon) in 2022 is the lowest full moon in the northern hemisphere since 2008.[18-19]
2022 Super Moon
2023
There will be 13 full moons in 2023.There will be two full moons (August 2 and August 31) in the middle of August of the Gregorian calendar.
At 2:32 a.m. on August 2, the moon, the earth and the sun aligned in a straight line. At this time, the moon was the roundest.At 13:52 that day, the moon was the closest to the earth, only 357311 kilometers away. The moon had the largest apparent diameter, with an angular distance of 33.4 minutes, which was larger than the apparent diameter of the sun at any time of the year.[20]
The "super moon" in 2023 will occur on August 31, with an apparent diameter of 32.95 cm.On August 2, August 31 and September 29, you can see three big moons in a row.The full moon on September 29 occurred at 17:57 shortly after the moon rose.The smallest full moon occurred on February 6, with an apparent diameter of 29.83 cm.The maximum full moon of this year is 10.12% larger than the minimum full moon.[21]
On August 30, 2023, the largest "super moon" in 2023 will appear in the night sky.At 23:54 on August 30, the moon passed the perigee (about 3571810 kilometers away from the earth). At this time, the moon's apparent diameter was the largest, which was the best time to watch.[22]
On September 29, 2023, the Mid Autumn Moon is the third largest full moon of the year and also the "super moon".[21]
2024
In the early morning of August 20, 2024, the first "super moon" in 2024 willAppear in the night sky.The full moon appeared at 2:26 on the 20th, and the moon's perigee appeared at 13:00 on the 21st.The next three times were on September 18, October 17 and November 16.Among them, the "super moon" on September 18 is the largest full moon of the year.[23]The "super moon" and the Mid Autumn full moon almost coincide perfectly, appearing only once every 60 years on average.[25]
Future trends
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1. Astronomical experts have calculated that the "super moon" on November 25, 2034 is only 356446km away from the earth, which is the first time that the distance between the moon and the earth is less than 356500km in the 21st century, that is, the "super super moon" appears for the first time in this century.The most recent "super moon" in this century appeared on December 6, 2052, when the distance between the earth and the moon was 356425 kilometers.
2. A voice on the Internet said that in the future, the "super moon" and "super super moon" will become smaller and smaller, because the moon is moving away from the earth at a speed of 3.8 cm every year.Theoretically, compared with the last big cycle, the "super moon" and "super super moon" will be smaller in the next big cycle of the moon's movement. But even after 10000 years, the difference is only 380 meters. In addition, at a speed of 1 meter a year, the distance from the calculation is only 10 kilometers, and this perigee difference is only 10 kilometers,At full moon, the size of the moon gives people no difference in vision.
social influence
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Internet rumor
Every time the "super moon" comes, the voice of "super moon" leading to the earth disaster spreads in cyberspace.A frightening statement is that due to the "close proximity" between the earth and the moon, the increase of the moon's gravity will affect the earth's plates, thus triggering large-scale earthquakes, volcanoes, tsunamis and other natural disasters.In addition, the "super moon" will also cause unusual weather on the earth.
Some good people said that there were super moons in 1955, 1974, 1992, 2005 and 2011, which did not bring good luck to mankind, and extreme weather events emerged in endlessly.For example, when the moon reached its perigee in 1938 and 1955, the United States and Australia were hit by hurricanes and floods respectively;On Christmas Day in 1974, Australia was hit by the strongest hurricane in history, Tracy;In January 2005, two weeks before the appearance of the super moon, a large-scale tsunami occurred in Indonesia, killing thousands of people;On March 8, 2011, a magnitude 4.3 earthquake occurred at the junction of Taikang County, Fugou County and Xihua County in Zhoukou City, Henan Province. On March 10, a magnitude 5.8 earthquake occurred in Yingjiang County, Yunnan Province. On March 11, a magnitude 9.0 earthquake and tsunami occurred near the east coast of Japan.Many people associate these disasters with the "super moon".
The question is, do they really have a necessary connection?
Experts refute rumors
In fact, the appearance of "super moon" and "super super moon" is actually a relatively normal astronomical phenomenon, with stronger repeatability and visibility than other celestial phenomena. We can see the appearance of "super moon" every year.
After running in in billions of years, the earth and the moon have formed a stable earth moon system. Therefore, even if they reach perigee, they will not cause disaster to the earth. At present, there is no evidence to support this conclusion.
Peter Wheeler, an expert at the International Radio Astronomy Center, also said that the "super moon" has no inevitable connection with earthquakes and volcanic eruptions. Even if volcanoes and earthquakes occur, it is mainly because of the Earth itself.
Zhao Junliang, former director of the Shanghai Observatory of the Chinese Academy of Sciences and a famous astronomer, said, "The distance between the earth and the moon does affect the earth's tides, but earthquakes are plate movements inside the earth."
Zhao Zhiheng, an expert in astronomy education and director of Tianjin Astronomical Society, said that there was no evidence to show that the distance between the earth and the moon was related to earthquakes or volcanic eruptions. Even if volcanoes and earthquakes occurred, it was also because of the earth itself.At present, it is recognized by the scientific community that the distance between the earth and the moon will only affect the tides of rivers and seas.[11]
Experts from the Institute of Geophysics of the China Seismological Bureau have studied the time series of disastrous earthquakes that have killed more than 1000 people since 1900 and the time series of large-scale volcanic eruptions with an eruption index of more than 4: By the middle of March 2011, there had been 108 seismic events that have killed more than 1000 people but less than 10000 people since 1900, with an average of once a year,The total number of earthquake events that killed more than 10000 people was 31, which occurred once every 3.5 years on average.From the time axis, the occurrence and distribution of such earthquakes are relatively uniform, and there is no clear corresponding relationship with the so-called "super moon".[12]
And some catastrophes, such as the huge earthquake in Chile and the huge tsunami caused by it, did not occur in 1955 of the "Super Moon Year", but in 1960;The Tangshan earthquake that killed 240000 people catastrophically in 1976, the Wenchuan earthquake that killed more than 80000 people in 2008, and the Haiti earthquake that killed more than 220000 people in 2010 were also not in the so-called "Super Moon Year".
As a part of the solar system, many scientists do not deny that the interplanetary movement in the solar system will have some impact on the earth. At present, many scientists in the world are also engaged in research in this field, but there is no evidence that the movement of the moon will cause disasters to the earth.Although the motion of the moon will change the tide size of the earth, it will not change too much.When the "super moon" appears, because the moon is closer to the earth, it will lead to a larger tide, but ordinary observers will not have too obvious feeling, nor will it cause serious natural disasters.
One view is that there is a part of the earth's interior that is liquid, so there will also be tidal movement. Some people think that the tidal movement of the earth's interior is one of the reasons for inducing earthquakes. In addition to being affected by the sun, this is obviously also affected by the movement of the moon, and the "super moon" will bring the greatest impact.However, at present, this statement also lacks sufficient scientific basis.
