The slogan of China Academy of Sciences

The answer is the moon. There is a crescent moon in the first month, a crescent moon with teeth in the old age and a full moon without teeth in the middle age.

The diameter of the moon is about a quarter of that of the earth, and its mass is about one-eighty-first of that of the earth. Its surface is covered with craters formed by the impact of small celestial bodies. The average distance between the moon and the earth is about 384,400 kilometers, which is about 30 times the diameter of the earth.

19, 16 In May, the National Astronomical Observatory of the Chinese Academy of Sciences announced that the research team led by Li Chunlai, a researcher of the Observatory, used Chang 'e-4 data to prove that there were deep substances mainly composed of olivine and low-calcium pyroxene in the Antarctic-aitken basin on the back of the moon. The international academic journal Nature published this important discovery online.

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Structural characteristics of the moon

The moon itself does not shine, but reflects sunlight. The brightness of the moon varies with the angular distance between the sun and the moon and the distance between the earth and the moon. The brightness at the full moon is more than ten times higher than that at the top and bottom chords. ?

The average brightness of the moon is 1/465000 of the brightness of the sun, and the brightness varies from 1/630000 to 1/375000. The average brightness at the full moon is-12.7, etc. Its average illumination to the earth is 0.22 lux, which is equivalent to the illumination of 100 watt electric lamp at a distance of 2 1 meter.

The surface of the moon is not a good reflector, and its average albedo is only 9%, and the other 9 1% is absorbed by the moon. The albedo of Guangdong Sea is even lower, about 7%. The albedo of the lunar highlands and craters is 17%, and it seems that the mountains are brighter than the moon sea.

The distance from the moon to the earth is about 1/400 of the distance from the earth to the sun, so the moon is as big as the earth to the sun.