Comet is a kind of rare celestial body with peculiar appearance, which is easy to attract people's attention. People naturally want to ask: What the hell is going on?
In ancient China, comets were regarded as celestial bodies at the earliest, and there were some good opinions. For example, in 1973, the picture of 1 comet was unearthed from Mawangdui Han Tomb in Changsha, Hunan Province. According to textual research, it was painted more than 200 years BC. There are more than 20 different shapes of comets in the picture, including nucleus, coma and tail. In particular, the tail of the comet is described in detail, including thick, thin, curved and divided into several branches. Comets are roughly classified according to their morphology.
The reason why comets shine is also well understood. Like Jin Shu? Tian said: "There is no light in the comet, but there is light in the daytime. Therefore, when you see it at night, it means east, and when you see it in the morning, it means west. Japan's north and south refer to the sun, and its awn is frustrated, long or short. " This is consistent with the modern view. Valuably, this view came from before the Jin Dynasty, and the correct view of comets in Europe was much later than that in China.
In ancient Europe, comets were not regarded as celestial bodies, but as phenomena in the earth's atmosphere. Aristotle, a Greek scholar in the 4th century BC, and his successors always regarded comets as burning phenomena in the earth's atmosphere. This view has far-reaching influence, so comets have long been regarded as meteorological categories. In BC 1 century, Ptolemy, a famous Greek astronomer living in Alexandria, Egypt, did not regard comets as celestial bodies in his book Astronomy. Until16th century, Copernicus, an outstanding astronomer in Poland, did not get rid of the old idea of comets. He said: "The upper atmosphere is considered to be the place where it was born." More than 30 years after Copernicus' death, 1 a great comet appeared in 577. Danish astronomer Tycho? Bula tried to measure the distance between the comet and the earth, but he didn't get any results because there was no correct measurement method, but he realized that the distance between the earth and the comet was at least six times farther than that of the moon, which showed that the comet was not a phenomenon in the earth's atmosphere. Tycho? Bula is the first person in Europe to regard a comet as a celestial body. Later, his student, German astronomer Képler, proved that Tycho? Bra's point of view.
/kloc-Kepler summed up the three laws of planetary motion in the 6th century, and Newton discovered the law of universal gravitation in the 7th century. So far, the orbit of comets can be calculated. 1680, 1 a big comet appeared, and Newton determined its orbit around the sun according to the observation data. Then in 1682, another 1 big comet appeared. British astronomer Harley cooperated with Newton to calculate the orbit of this comet. Harley devoted a lot of energy to the study of this comet. He sorted out the records of previous comets and calculated the orbits of 24 comets observed from 1337 to 1698. 1695, Harley discovered the orbits of three comets, which is very noteworthy. 1 was observed at 153 1 by Apeon, 1607 by Kepler and 1682 by Harley. After careful consideration, Harley thinks that this may be the three returns of the same comet. But there is still a problem. If it's the same comet, why are the weekly intervals different? Some are 74 years 1 1 month, and some are 76 years and two months. Why? But after all, Harley is a scholar with high knowledge of mathematics and physics. He believes that this may be due to the perturbation of Saturn and Jupiter on this comet, which makes its orbit and period different. He finally confirmed that these three times were the same comet. Then the forecast will come back at 1758. Sure enough, he came back in February of 1758, and Harley couldn't see it. He died in 1742. To commemorate the great discovery of this scholar, this comet was named "Halley's Comet". Harley was the first person in the world to discover periodic comets, which proved that comets, like planets, are celestial bodies orbiting the sun under the control of gravity.
At this point, the understanding of comets can be said to be a leap, thus laying a solid foundation for the future study of comets.
By the 1940s of 19, we still didn't know what composition comets were made of. The French philosopher Comte once said in 1842: "We can't study the chemical composition of celestial bodies at any time and under any circumstances". Less than 20 years ago, photography and spectral analysis were widely used in astronomical observation, which solved the problems of chemical composition, luminescence and physical properties of comets.
Now, the understanding of comets has entered a new stage.