  After a thorough research on the circumstantial changes and the great
evolution of life in the Cambrian period, the author propounds such a
hypothesis: During the Late Precambrian, about 500-600Ma, a celestial body
impacted the Earth. The high temperature ended the great glaciation,
facilitated the communication of biological information. The rapid change of
Earth environment enkindled the genesis-control system, and released the HSP-90
variations. After the impact, benefited from the protection of the new ozone
layer and the energy supplement of the aerobic respiration, those survived
underground life exploded. They generated carapaces and complex metabolism to
adjust to the new circumstance of high temperature and high pressure.
  This article uses a large amount of analyses and calculations, and
illustrates that this hypothesis fits well with most of the important
incidences in astronomic and geologic discoveries.
