Archiv: Erdgeschichte / Geologische Zeitskala / geological time scale


30.05.2019 - 16:11 [ arxiv.org ]

Hypothesis: Muon Radiation Dose and Marine Megafaunal Extinction at the end-Pliocene Supernova

(November 2018)

Considerable data and analysis support the detection of one or more supernovae (SNe) at a distance of about 50 pc, ∼2.6 million years ago. This is possibly related to the extinction event around that time and is a member of a series of explosions that formed the Local Bubble in the interstellar medium. We build on previous work, and propagate the muon flux from SN-initiated cosmic rays from the surface to the depths of the ocean. We find that the radiation dose from the muons will exceed the total present surface dose from all sources at depths up to 1 km and will persist for at least the lifetime of marine megafauna. It is reasonable to hypothesize that this increase in radiation load may have contributed to a newly documented marine megafaunal extinction at that time.

30.05.2019 - 15:49 [ Researchgate.net ]

Cosmic-ray volleys from the Galactic Center and their recent impact on the earth environment

(March 1987)

7. Conclusions

The folowing conclusions are proposed:

1) Periodically the center of our galaxy enters an explsive phase during which it generates an outburst of cosmic rays in the form of highly relativistic electrons and positrons with total particle energies of 10 to the power of 57 ergs or more.
2) These outburst last anywhere from several hundred to several thousand years, major events recurring about once every 5000-15000 years.