A brief discussion on astronomical phenomena caused by changes in the moon’s orbit. Is the super moon coming again in May?

The super moon on May 7 will be the largest and last one in 2020!

In fact, there are four opportunities to watch the super moon in January 2020. If you missed the first three times, then don’t forget the largest super moon on the night of May 7. This This is also the last chance to watch the super moon this year.

The best time to watch the super moon

It will appear from 18:45 pm on May 7 to 2:09 am on April 8 when the moon moves into its own At perigee, the moon, earth and sun will be aligned in the same straight line at 10:35 on the 8th. During this period, everyone can see the super moon.

Of course, in terms of visual effects, if you want to see the moment when the moon is the largest and roundest, then it is best to choose when the moon phase is full. The reason why everyone will see a larger and brighter moon phase in the early morning of the 8th is because the moon at that time will be the closest to the earth in a year.

Is this super moon visible across the country?

Unlike other astronomical wonders, which have strict requirements on the location and observation time of viewers, this super moon can be seen from all over the country. There are only two prerequisites that need to be met:

First: The so-called unpredictable weather. Although no matter what the weather is in your location, it cannot prevent the super moon from happening, but bad weather such as rain can prevent the super moon from happening. The weather will inevitably prevent everyone from seeing this super moon.

Second: Since as long as the weather is fine, people everywhere can witness the super moon with their own eyes. Since there is no weather to cause trouble, everyone needs to take a step outdoors, and the super moon You will definitely arrive on time as scheduled. This time, both ordinary cameras and professional astronomical telescope equipment can easily capture the super moon in the sky. ?

When is the next supermoon?

In fact, super moons are not a particularly rare astronomical spectacle. We can see from historical data in previous years that super moons appear almost every year 4 to 6 times. For example, the super moon phenomenon occurred as many as 6 times in 2015, and there will be 4 super moons in 2020.

If you miss this super moon again due to rain or other reasons, don’t feel particularly sorry, because it will be about a year later, on May 26, 2021 , we will usher in the next super moon.

The nature of the super moon

Many people may not know that the term super moon was first proposed in 1979, not by an astronomical scientist, but by a man named Richard Noelle American Astrologer. The essence of a super moon is actually the lunar phase of a new moon or full moon that appears after the moon moves near the earth's perigee.

The reason why the moon phase that appears at this special time is called a super moon is because when the distance between the earth and the moon is close enough, the moon seen by our eyes will be much larger than usual (perigee) The full moon will be about 14% larger than the apogee full moon). In fact, not all astronomers think that the name super moon is reasonable. To be precise, it should be called a perigee full moon.

The formation principle of the super moon

As the only natural satellite of the earth, people from ancient times to the present have a special affection for the moon. Although research shows that the moon is gradually moving away Our earth, but if it were not placed on a very long timeline, everyone would hardly feel the basic fact that the earth and the moon have become farther and farther away.

When we describe the distance between the Earth and the Moon, we generally use the term average distance. This is because both planets are constantly moving and it is difficult to give an accurate distance value. In fact, just as our Earth is an approximately perfect elliptical sphere, the moon's orbit around the Earth is also elliptical. When the Moon is at perigee and apogee, its average distances are 363,000 kilometers and 363,000 kilometers respectively. 406,000 kilometers.

The super moon actually stems from the 10.41% gap between the moon's near-Earth distance and its far distance, and the reason is very simple. For us living on the earth, when the distance between the earth and the moon becomes closer, this means that the moon we see will become larger; when the distance between the moon and the earth becomes further, then , the moon we see will also become smaller.

The reason why it is difficult for us to feel the change in the size of the moon at ordinary times, but when the super moon appears, we will obviously notice that the moon has become larger. In fact, it is the visual effect caused by the 5 kilometers distance difference. difference.

How to calculate the time when the super moon will appear?

Whether it is how many super moons will appear in a year or the time when each super moon will appear, it can actually be calculated in advance. As we all know, 27.32 days is the revolution period of the moon, but the average period of the lunar synodic month is 29.35 days. The time difference between these two cycles means that the moon needs about 2 more days to rotate for the moon phase to return to the new moon (27.3*(1 +27.3/365)=29.4).

When calculated from the calendar, we will find that the 15 perigee full moons are actually very close to the 14 synodic moons. In other words, it is equivalent to a super moon occurring only 413 days apart. However, since this calculation method may lead to similar situations one month before and after the time, the full moons that appear during these periods are gradually being replaced. Many people call it a super moon.

The reason why the appearance of super moons is extremely cyclical is mainly because even on a time scale of hundreds of years, neither the orbit of the moon nor the orbit of the earth will change. Fundamental changes have taken place, so the lunar and solar eclipses that everyone pays special attention to also appear regularly like super moons.