On the record in the night of April 5, 687B.C.: stars were not seen and stars fell like rain at midnight

A long time insoluble mystery is why the night stars were not seen; in a paragraph recorded in Chun Qiu which was one night during the ``Xin Mao'' in April in the seventh year of Lu Zhuang-gong (687.B.C) in night, the stars were not seen and in midnight the stars fell like rain. '' Historically, most of the scholars had considered that ``stars not seen '' and ``stars fell like rain ''as two phenomena not related. On the basis of the brightness in the sky when Leonids appeared in 1533 researched in 1994, collating the relative date ancient and modern, Chinese and foreign, the author found the reason that the stars were not seen in fact was the brightness in sky given by meteor shower. The phenomenon that the stars were not seen and the stars fell like rain at the same period, in midnight are proved concisely. The density of the meteor shower appeared, the sum total of the meteor, the mass of the meteor eclipsing the light of the stars and the area of the concealed stars are also estimated.