Archiv: extinction periodes


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 - 15:55 [ New York Times ]

STUDY HINTS EXTINCTIONS STRIKE IN SET INTERVALS

(11. Dezember 1983)

At a conference on mass extinctions, held in August at Northern Arizona University in Flagstaff, Dr. Sepkoski said the timing of these events suggested that “there is indeed a statistically significant periodicity in the observed distribution of events of mass or accelerated extinction over the last 250 million years.“ Search for Answers

He confessed this “stumped“ him and Dr. Raup, saying: “We are aware of no documented process with a cycling time approximately 26 million years. But with that long a cycle, we suspect that the forcing agent will not be terrestrial but rather solar or galactic.“

30.05.2019 - 15:49 [ Harvard.edu ]

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

Authors: Laviolette, P. A.
Journal: Earth, Moon, and Planets (ISSN 0167-9295), vol. 37, March 1987, p. 241-286.