Biological implications of high-energy cosmic ray induced muon flux in the extragalactic shock model

TL;DR

This study investigates how increased muon radiation from high-energy cosmic rays, linked to our galaxy's motion, may influence Earth's biodiversity over geological timescales.

Contribution

It models the biological radiation dose from cosmic ray-induced muons and explores its potential impact on terrestrial biodiversity variations.

Findings

Muon flux increases during galactic shock periods.

Enhanced muon dose correlates with biodiversity cycles.

Implications for cosmic ray influence on evolution.

Abstract

A ~ 62 My periodicity in fossil biodiversity has been observed in independent studies of paleontology databases over ~0.5Gy. The period and phase of this biodiversity cycle coincides with the oscillation of our solar system normal to the galactic disk with an amplitude ~70 parsecs and a period ~64 My. Our Galaxy is falling toward the Virgo cluster, forming a galactic shock at the north end of our galaxy due to this motion, capable of accelerating particles and exposing our galaxy's northern side to a higher flux of cosmic rays. These high-energy particles strike the Earth's atmosphere initiating extensive air showers, ionizing the atmosphere by producing charged secondary particles. Secondary particles such as muons produced as a result of nuclear interactions are able to reach the ground and enhance the biological radiation dose. Using a Monte Carlo simulation package CORSIKA, we compute the biological dose resulting from enhanced muon exposure from cosmic rays and discuss their implications for terrestrial biodiversity variations.