All-Moscow Seminar of Astrophysicists
(ASA)
The seminar is supported by the grant of Federal Programm "Integration"
annotation of talk
V.M.Byakov, S.V.Stepanov (ITEP)
"Role of Ionizing Radiation in the Natural History of the Earth"
The Solar system, oscillating relative the Galaxy midplane during its
revolution around the Galactic center, can occasionally fall inside the
gas-dust interstellar clouds, which include remnants of Supernova (SN)
explosions. These are mainly accumulated in the vicinity of the Galactic
midplane. Being the main sources of the cosmic rays, such remnants are
characterized by a high density of relativistic particles. The long time
stayings of the Earth inside the young SN remnants could induce mass
extinctions of the highest, most radiosensitive living organisms and
specific global geochemical effects. We show that the probability that the
Earth meets a SN remnant in dangerous proximity during one of the Sun's
passings through the Galaxy disk is about unity. Thus, the half-period of
the Solar System's oscillations, which slightly exceeds 30 MY, turns out to
be a natural time unit for chronologization in the Earth history. Some its
well known global events and phenomena are considered as evidences of the
quasiregular stayings of the Earth in the SN remnants.