Isn t it once every few years in a solar eclipse, how can it be said that it is once in 500 years?

A solar eclipse is not actually a once-in-500-year event.

There are three main types of solar eclipses: total solar eclipses, partial solar eclipses, and annular solar eclipses. Solar eclipses occur on the principle that parts of the Earth are obscured by the shadow of the moon. The eclipse must occur on the New Year's Day, the first day of the lunar calendar.

This is because only on that day will the Moon appear on the line between the Sun and the Earth, so that it is possible for the Moon to block the Sun and form a solar eclipse. Similarly, a lunar eclipse must occur on the 15th day of the lunar calendar. The 500 years here refers to a total solar eclipse.

In fact, there will be a solar eclipse on the first day of every month, of course, you may not see it, because the shadow of the moon does not necessarily fall on the earth, it is more difficult to fall in China, and it is even less common when you pass through the window of your house. But not every fifteenth day of the month there will be a lunar eclipse. This is because apart from the above conditions, there are several other factors that influence the occurrence of solar and lunar eclipses.

We call the Earth's orbit around the Sun the ecliptic, and the Moon's orbit around the Earth the white path. The plane of the ecliptic is not the same as the plane of the white plane, and there is an average angle of 5°09 between them, which can change at any time. Of course this is off-topic about lunar eclipses, but the principle is similar.

The law and cycle of solar eclipsesSince the earth's orbital motion around the sun and moon around the earth and the movement of the yellow and white nodes are regular, a roughly similar solar and lunar eclipse will occur at a certain time. As early as ancient times, the Babylonians, based on long-term statistics of solar and lunar eclipses, discovered that the cycle of solar and lunar eclipses was 233 synodic months, that is, 18 years 11 and 1 3 days, that is, the Saro cycle. That is to say, the least common multiple of the lunar eclipse cycle and the solar eclipse cycle is called the Saros cycle.

And this time, once in 500 years, it refers to the long duration, and there will be another time after 500 years. I don't know if you've seen it this time.

Solar eclipses are frequent, solar eclipses include partial solar eclipses and total solar eclipses, total solar eclipses are not easily visible in the same area, total solar eclipses that can be seen in the middle and lower reaches of the Yangtze River, the last time occurred in 1575, and the next time will be in 2309.

It means a solar eclipse on a large scale in our country. There are many factors, such as the whole journey time is only more than two hours, and the longitude of the earth that can be crossed is more than 30 degrees, which can just fall in China, which is rare.

That's just for China, because this time there are dozens of regions in China that will be able to see the total solar eclipse. A total solar eclipse occurs every 2 years around the world, but each time it involves a different country and location.

The main reason why a total solar eclipse is valued is that it is of great astronomical value. There have been many major astronomical and physical discoveries in the history of science that have been made using the opportunity of total solar eclipses, and only through such chances. The most famous example is a total solar eclipse in 1919, which confirmed the correctness of Einstein's general theory of relativity.

Solar eclipses occur once a year on average, but are only seen once in about 300 years at the same location.

In folklore, this phenomenon is called the Tengu Eclipse Day. Solar eclipses only occur at the New Year, when the Moon and the Sun are conjunct. Solar eclipses are divided into partial solar eclipses, total solar eclipses, annular solar eclipses, and total annular eclipses.

You can't look directly at the sun when observing a solar eclipse, otherwise it will cause temporary blindness, and in severe cases, permanent blindness.

Follow me toAstronomical phenomenaLook at how many years a solar eclipse is? How many times will you see each other in your life? Solar eclipses are at least twice a year.

Because the plane of the Earth's orbit has an angle to the plane of the Moon's orbit, there are two points of intersection. In this way, as long as the Sun and Moon move to these two nodes, a solar and lunar eclipse will occur.

For the same place, it is okay to ask how many years a solar eclipse occurs, for a given location, on average, a partial solar eclipse can only be seen every 3 years or so, and it is only after 300 years that you can dig up finch juice to see a total solar eclipse.

But for the whole world, solar eclipses do not occur so rarely, there are also at least 2 solar eclipses a year, and up to 5 solar eclipses.

Solar eclipses do not occur at equal intervals, but follow a cycle - the Saro cycle, which refers to a period of time with a length of 6 days, that is, about 18 years, 11 days and 8 hours, during which there are 71 eclipses, including 43 solar eclipses and 28 lunar eclipses.

Because after that period of time, the position of the Earth, the Moon and the Sun returns to exactly the same relative position, so the same solar eclipse or lunar eclipse will occur, but because the positions of these three do not take into account the position of the Earth's rotation, two eclipses of the same nature that occur at intervals of such a cycle will not occur in the same place.

For example, on July 11, 1991, there was a total solar eclipse that passed through Latin America and the Pacific. Going forward 18 years and 11 days, there must have been a solar eclipse on June 30, 1973, which was found to be the case, and the occult eclipse of the total eclipse crossed the continent. If we push back the time of the Salo cycle, one can calculate that there will also be a solar eclipse on July 22, 2009, which is a total solar eclipse in the Yangtze River basin of China.

In this year, there were two solar eclipses in 2016, a total solar eclipse on March 9 and an annular solar eclipse on September 1.

Sometimes, there are up to 5 solar and 2 lunar eclipses in a year. Sometimes, the sun and moon can occur four and three times a year, respectively; Solar eclipses occur at least twice a year, and lunar eclipses may not occur once a year. Half a month after a solar eclipse, a lunar eclipse is possible.

In short, it happens every year. However, since the solar eclipse can only be seen in certain areas during the day, and the lunar eclipse can be seen half of the world at night, it seems that the lunar eclipse is much more than the solar eclipse. Some people don't see a solar eclipse once in their lifetime, and some people see all the solar and lunar eclipses in half a month.

Solar and lunar eclipses follow the eclipse year, which is the Salo cycle, which cycles once a year.

So solar and lunar eclipses are regular. But it's not a perfect coincidence with an integer year. Even if you calculate the date and time of a solar or lunar eclipse, it may be different from the last one, because the distance between the moon and the earth may be affected by the influence of planets and stars, such as a total solar eclipse becoming an annular solar eclipse.

Each solar eclipse lasts up to 2 hours and each lunar eclipse lasts up to 3 and a half hours.

The cause of the eclipse is the intersection of the ecliptic and the white way, and as long as the intersection point is in a straight line with the Sun and the Earth, and the Moon is moving nearby, the eclipse may occur, and this time is called the eclipse season.

The eclipse season is 36 days, which covers the length of a synodic month, so a solar eclipse is bound to occur during the eclipse season, and if the circumstances are exceptional, it can occur twice. There is a feeding season every six months. However, sometimes there are two half-eclipses a year, because the yellow and white nodes are affected by the sun's gravity and move clockwise, so the eclipse year is 19 days shorter than the sidereal year.

So in exceptional cases, there will be two complete and one incomplete season, or two incomplete and one complete season. The former will cause 5 solar eclipses and 2 lunar eclipses; The latter may be 4 times, 3 times.