Solar eclipse and lunar eclipse data

Lunar eclipse means that the moon goes around the earth and moves between the sun and the earth. At this time, it is the first day of the first lunar month. If the sun, the moon and the earth are in a straight line, the moon blocks the sunlight that hits the earth, and the shadow behind the moon just falls on the earth, then a solar eclipse occurs. People in the shadow of the moon on the earth began to see the sun gradually weakening, and the sun was covered by a circular shadow. When the sky is dark and completely covered, the brightest stars and planets can be seen in the sky. After a few minutes, the sun gradually emerged from the shadow edge of the moon and began to shine and make the last contact. Because the moon is smaller than the earth, only people in the shadow of the moon can see the solar eclipse. Total lunar eclipse occurs when the moon blocks all the sun, partial solar eclipse occurs when the moon blocks part of the sun, and annular solar eclipse occurs when the moon blocks the central part of the sun. The total solar eclipse lasts no more than 7 minutes and 58 seconds. China has the oldest solar eclipse record in the world, and there have been exact solar eclipse records for over 0/000 years BC.

Whether it is a partial solar eclipse, a total solar eclipse or an annular solar eclipse, the time is very short. Watch the total solar eclipse in the same place for no more than seven minutes and forty-five seconds. The area where the solar eclipse can be seen on the earth is also limited, because the moon is relatively small and its umbra is relatively small and short, so the umbra will not sweep the earth for a long time. Because the average length of the umbra of the moon (373,293 kilometers) is shorter than the average distance between the moon and the earth (384,400 kilometers), there are more annular eclipses on the whole earth than total solar eclipses.

solar prominence

Prominence is a kind of solar activity phenomenon that protrudes beyond the edge of the sun's surface. When prominence appears, colored balls in the atmosphere resemble burning grasslands, and rose-red tongue-shaped gas rises like fire, with different shapes, some like clouds, some like arch bridges, some like fountains, some like clumps of grass, and some are as beautiful as festive fireworks. On the whole, they are shaped like earrings attached to the edge of the sun, hence the name "prominence".

Prominences rise about tens of thousands of kilometers. Large prominences can be hundreds of thousands of kilometers higher than the surface of the sun, with a general length of about 200,000 kilometers, and individual prominences can reach 1.5 million kilometers. Prominences are much darker than the photosphere, so they can't be observed with the naked eye at ordinary times, and can only be seen directly during a total solar eclipse.

Prominence is a very strange phenomenon of solar activity. Its temperature ranges from 5,000 to 8,000. Most prominences rise to a certain height and then slowly land on the surface of the sun. However, some prominences float in the lower layer of the corona, and the temperature is as high as 2 million K, which is as strange as a piece of unmelted ice in a hot steelmaking furnace. In addition, the density of prominence is 654,330 higher than that of corona.

The outermost atmosphere of the sun is called the corona. The corona extends several times to dozens of times the diameter of the sun. In the most active year of solar activity, the corona is close to a circle; In quiet years, it is oval.

There are large irregular dark areas in the corona, which are called coronal holes. Coronal hole is an area with low gas density in the corona. There are three kinds of coronal holes: polar coronal holes, isolated coronal holes and extended coronal holes. Solar energy loses material in the form of solar wind-material particle flow. Coronal hole is an important source of high-speed solar wind. Coronal mass ejection (CME) is a very macroscopic and huge material and magnetic field structure that occurs in the corona. It is a sudden explosion phenomenon of large-scale dense plasma. Nothing can affect the earth more than it. When there is a strong explosion and coronal mass ejection on the sun, the powerful plasma flow carried by the solar wind may reach the polar regions of the earth. At this time, the aurora appears at the poles of the earth. The forms of aurora are ever-changing. Aurora has also been found on some planets with magnetic fields in the solar system. Flares occurring in the corona are called X-ray flares, and their wavelength is only 1 ~ 8 Angstroms or less. It directly causes the disturbance of the earth's ionosphere, thus affecting the earth's short-wave communication.

Rilang

Surfing is also called "solar wave". An ejection phenomenon of solar photospheric matter. It usually occurs over sunspots and has strong reproducibility. When a broken wave falls behind along the rising path, it will trigger a new broken wave to take off, and so on, but the scale and height are getting smaller and smaller every time until it disappears.

Surfing at the edge of the sun looks like a bright hill with a sharp peak at the top. The height of the rise is different. Small surfing is only a few hundred kilometers, big surfing can reach 5000 kilometers, and the maximum surfing can reach 1 ~ 20000 kilometers. The maximum speed of the projectile can reach 100 ~ 200 kilometers per second, which is more than 100 times faster than the fastest reconnaissance plane. When they reach the highest point, they begin to descend under the influence of the sun's gravity until they return to the surface of the sun. From the high-resolution observation data, it is found that surfing is composed of a very small bundle of fibers, and each bundle of fibers is very small apart, which shines and moves together as a whole.

Solar activity forecast

The change of the state of space environment between the sun and the earth is becoming more and more important to the modern cutting-edge technology on which modern life and production depend. As mentioned earlier, X-ray flares directly cause ionospheric disturbances on the earth, thus affecting short-wave communication on the earth. Solar proton events will endanger the sensors and control equipment of astronauts and spacecraft, and also pose a radiation threat to passengers and crew flying at high latitudes. According to statistics, strong solar activity is related to earthquakes, volcanic eruptions, droughts and floods, heart and nervous system diseases and traffic accidents. Therefore, solar activity and solar-terrestrial physical prediction are very important. Solar activity forecasting is divided into long-term, medium-term and short-term forecasting and early warning.

As a systematic scientific research object, the space environment of the sun and the earth began in 1957 when humans entered space. The 1950s and 1970s were the exploration stages, and people gradually realized the importance of space environment. On the basis of a lot of exploration, a static model describing the environment is established and some important spatial activities are predicted. After 1980s, driven by demand, the research on the space environment of the sun and the earth developed rapidly. Since 1979, the international conference on solar-terrestrial prediction has been held as scheduled every four years, and its scale has been expanding. In order to unite and coordinate the work of major countries, a joint forecasting center was established. Headquartered in the United States, there are 10 regional alarm centers distributed all over the world. Our Beijing alarm center is one of them. After entering the 1990s, scientists vividly called it "space weather".

Solar activity cycle

Time interval of several important solar activities. The average period is 22 years, and it includes two sunspot cycles of 1 1 year. In each cycle, the polarity of sunspots is opposite, and the changes of other solar phenomena have two highs and two lows like sunspots. These solar phenomena include prominence, flare and frequency fluctuation of magnetic effect, and magnetic effect includes aurora and enhancement of radio interference to the earth. The basic sunspot cycle (sometimes called solar activity cycle) of1year was announced by Schwabe in 1843. Some people try to link the solar activity cycle with the changes of other phenomena, such as the slight change of the diameter of the sun, the change of tree rings, and even the fluctuation of the stock market.

lunar eclipse

Eclipse is a special astronomical phenomenon, which means that when the moon moves to the shadow of the earth, the area between the moon and the earth will be blocked by the earth because of sunlight. Now we see that the moon is missing a piece.

That is to say, at this time, the sun, the earth and the moon are just (or almost) in a straight line, so the light from the sun to the moon will be blocked by the earth.

As far as the earth is concerned, when an eclipse occurs, the directions of the sun and the moon will be different by 180 degrees, so the eclipse must occur at' Wang' (that is, around the lunar calendar 15). It should be noted that the orbits of the sun and the moon in the sky (called the ecliptic and the ecliptic) are not on the same plane, but have an intersection angle of about 5 degrees, so only when the sun and the moon are located near the intersection of the ecliptic and the ecliptic can they be connected in a straight line to produce an eclipse.

Classification of lunar eclipse

The diameter of the earth is about four times that of the moon. In lunar orbit, the umbra diameter of the earth is still 2.5 times that of the moon. So when the centers of the earth and the moon are roughly on the same straight line, the moon will completely enter the umbra of the earth, resulting in a total lunar eclipse. But if only a part of the moon is always covered by the umbra of the earth, that is, only a part of the moon enters the umbra of the earth, a partial lunar eclipse will occur.

The diameter of the sun is much larger than that of the earth, and the shadow of the earth can be divided into umbra and penumbra. If the moon enters the penumbra, the sunlight will also be blocked. This phenomenon is called penumbral eclipse in astronomy. Because the sun in the penumbra is still very strong, the brightness of the lunar surface is only slightly weakened. In most cases, the penumbra eclipse is not easy to distinguish with the naked eye. In general, because it is not easy to be found, it is not called an eclipse, so there are only two kinds of total solar eclipse and partial solar eclipse.

In addition, because the umbra of the earth is much larger than that of the moon, it also means that in the event of a total lunar eclipse, the moon will completely enter the umbra of the earth, so there will be no eclipse.

The number of solar eclipses occurs twice a year, up to three times, and sometimes none at all. Because under normal circumstances, the moon either passes above the Earth's umbra or leaves from below, rarely or partially passes through the Earth's umbra, so an eclipse will not occur under normal circumstances.

According to the statistics of observation data, the percentage of lunar eclipse, partial eclipse and total eclipse in the penumbra in each century is about 36.60%, 34.46% and 28.94%.

The process of lunar eclipse

After the total lunar eclipse, the penumbra begins to eclipse: the moon just touches the penumbra, which is invisible to the naked eye at this time.

The process of a formal eclipse can be divided into five stages: initial loss, eclipse, eclipse, luminescence and last contact.

The first loss: marks the beginning of the solar eclipse. The moon slowly entered the shadow from the eastern edge, and the umbra of the moon and the earth was delineated for the first time.

Eclipse: The western edge of the moon is inscribed with the western edge of the Earth's umbra, and the moon just enters the Earth's umbra.

Eclipse: The center of the moon is closest to the center of the Earth's umbra.

Luminescence: the eastern edge of the moon is inscribed with the eastern edge of the umbra of the earth, and the total solar eclipse phase ends at this time.

Final contact: the western edge of the moon is tangent to the eastern edge of the umbra of the earth. At this time, the whole eclipse was over.

The degree of eclipse is called "eclipse", which is equal to the ratio of the farthest distance from the edge of the moon wheel to the umbra of the earth and the meridian of the moon when the eclipse is serious.

End of the penumbra eclipse: The moon leaves the penumbra, and the whole eclipse process officially ends.

Eclipses and scientific research

Eclipses have been promoting the development of human understanding.

The earliest lunar eclipse was recorded in Mesopotamia in 2283. When China was in the Han Dynasty, Zhang Heng had discovered the principle of solar eclipse. Aristotle in the 4th century inferred that the earth was round according to the circle of the earth's shadow seen during the solar eclipse. Aristak, an astronomer in ancient Greece in the 3rd century, and Alistair in the 2nd century both proposed to measure the size of the sun, the earth and the moon by solar eclipse. Iba Valley also proposed to observe the lunar eclipse in two distant places at the same time to measure the geographical longitude. In the 2nd century AD, Ptolemy used the ancient lunar eclipse records to study the movement of the moon, and this method has continued to this day. Before the appearance of rockets and artificial earth satellites, scientists have been exploring the atmospheric structure of the earth by observing eclipses.

On the fifteenth and sixteenth days of the lunar calendar, the moon runs in the opposite direction to the sun. At this time, if the centers of the earth and the moon are roughly on the same straight line, the moon will enter the umbra of the earth and produce a total lunar eclipse. If only a part of the moon enters the umbra of the earth, a partial lunar eclipse will occur. When the moon enters the penumbra of the earth, it should be a penumbral eclipse, but it is not called an eclipse because the brightness drops very little, so there are only two kinds of eclipses: total eclipse and partial eclipse. Eclipses always occur in sight (full moon), but not every time, which is the same as not every new moon has an eclipse.

lunar eclipse

lunar eclipse

The phenomenon that the moon is completely or partially covered by the shadow of the earth. A solar eclipse usually occurs on the 15th or 16th day of each month in the summer calendar, when the earth moves between the sun and the moon, but not every ecliptic can happen, because there is an intersection between the ecliptic and the ecliptic, so only on a moonlit night, when the moon continuously takes photos of the solar eclipse, the earth's shadow can be seen near the intersection of the ecliptic and the ecliptic, can observers on the earth observe the solar eclipse. Generally speaking, the number of eclipses occurs twice a year. The diameter of the sun is much larger than that of the earth, and the shadow of the earth can be divided into umbra and penumbra. The diameter of the earth is about four times that of the moon. In lunar orbit, the umbra diameter of the earth is still 2.5 times that of the moon. When a part of the moon is always covered by the umbra of the earth, a partial lunar eclipse will occur. When the moon completely enters the umbra of the earth, you can see the total lunar eclipse. If the moon enters the penumbra, the sunlight will also be blocked. This phenomenon is called penumbral eclipse in astronomy. However, because the sunlight in the penumbra is still very strong, the penumbra eclipse is not easy to distinguish with the naked eye in most cases. However, penumbral eclipses often occur. According to the observation data, the percentage of penumbral eclipse, partial eclipse and total eclipse in each century is about 36.60% and 34.46%.