What's the difference between a solar eclipse and a 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 ancient Greek astronomer 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, only on a moonlit night can the moon take photos of the solar eclipse continuously, and the earth's shadow can be seen near the intersection of the ecliptic and the ecliptic, so observers on the earth can 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%.
■ solar eclipse
Total lunar eclipse is a special astronomical phenomenon, which means that when the moon moves to the shadow part of the earth, the area between the moon and the earth will be blocked by the earth because of sunlight, and now the moon is gone.
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 in Wangwang (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.
■ What kinds of eclipses are there?
Total lunar eclipse: when the whole moon enters the umbra of the earth.
Eclipse: When only a part of the moon enters the umbra of the earth.
Penumbral eclipse: at this time, the moon only passes through the penumbra of the earth, which leads to a slight decrease in the brightness of the moon surface, so it is difficult to be found.
■ Seven steps of total 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.
Initial loss: the moon slowly enters the shadow from the eastern edge, and the shadow of the moon and the earth is circumscribed for the first time.
Eclipse: The umbra of the moon entering the earth is engraved with the earth for the first time.
What to eat: the moment when the center of the full moon is closest to the center of the Earth's umbra.
Cold light: the moon moves in the umbra of the earth and is inscribed with the umbra of the earth for the second time.
Last contact: the moon gradually leaves the umbra of the earth and is circumscribed for the second time.
End of the penumbra eclipse: The moon leaves the penumbra, and the whole eclipse process officially ends.
The formation of lunar eclipse
Solar eclipse is a phenomenon in nature. When the sun, the earth and the moon are exactly or almost on the same straight line (the earth is between the sun and the moon), the light from the sun to the moon will be partially or completely blocked by the earth, resulting in an eclipse.
For the earth, the direction difference between the sun and the moon is 180, so the eclipse must occur in Wangwang (around the fifteenth day of the lunar calendar). It should be noted that the orbits of the sun and the moon in the sky (called ecliptic and ecliptic respectively) are not on the same plane, but have an intersection angle of about 5, so only when the sun and the moon are located near the intersection of ecliptic and ecliptic respectively can they form a straight line and produce an eclipse.
Eclipses can be divided into three types: partial eclipse, total eclipse and penumbral eclipse. When only a part of the moon enters the umbra of the earth, there will be a partial lunar eclipse; When the whole moon enters the umbra of the earth, a total lunar eclipse will occur. As for the penumbral eclipse, it means that the moon just passes through the penumbral region of the earth, which causes the brightness of the moon to be extremely slightly weakened, so it is difficult for the naked eye to see the difference, so it is not noticed by people.
Observe the brightness and color of the moon.
During the eclipse, the brightness and color of the lunar surface can be divided into the following five levels: level 0, which is very dim and almost invisible; 1, slightly bright, black and yellow, the details are difficult to distinguish; Grade 2, slightly bright, dark red or brown, with some dark spots in the middle and quite bright outside; Level 3, brick red, you can see the details of the moon, but it is very vague; Level 4, copper red, very bright, very bright outside, slightly blue, you can see big details. When observing the total lunar eclipse, it is necessary to judge the brightness and color scale of the lunar surface and record it. At the same time, record the weather at that time.
The moon goes around the earth once every 30 days. When we look at the stars at night, we won't find any changes in the positions of those stars relative to the moon. This time is different. During the whole eclipse, if you look carefully, you will find that the relative position of the moon and the stars has changed. Opportunity is rare, don't miss the first lunar eclipse of this century!
solar eclipse
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.