On this day, 41 years ago, December 27, 1984 (November 6, 1984, the lunar calendar), scientists collaborated to conduct scientific experiments on artificial comets. According to a joint research project costing US$78 million by the United States, the United Kingdom and the Federal Republic of Germany, an artificial satellite of the Federal Republic of Germany released a cloud of metallic barium at an altitude of 60,000 miles in the Pacific Ocean at about 4:30 a.m.(Pacific Standard Time) on December 27, 1984 to produce a comet-like celestial phenomenon-artificial comets. The observation aircraft quickly observed the appearance of a small comet with a head and a tail. This experiment is one of seven experiments in the joint research project of the three countries. It was originally scheduled to be carried out two days ago. It was postponed due to cloudy skies in Arizona, New Mexico and Hawaii in the United States, which would affect ground observations of artificial comets in these areas. Through this research, scientists hope to gain insight into the interaction between the solar wind and the Earth's magnetic field; the role played by collisions of space plasma with dust and gas in the formation of comets, planets and stars; how to control the plasma to utilize the energy generated by nuclear fusion; How the solar wind interferes with satellites and Earth's communications and power lines, and how it affects Earth's weather. Astronomers also plan to use this man-made comet to adjust equipment for studying Halley's Comet from late 1985 to early 1986. This man-made comet uses the energy of the sun to give off colored light. In vast areas of the western United States and places such as Hawaii, southwestern Canada, and Tahiti Island in the central Pacific, people can observe it for ten minutes with the naked eye on a clear night, and for an hour with a telescope.