Periodic mass extinctions and the Planet X model reconsidered

TL;DR

This paper reevaluates the Planet X hypothesis as an explanation for the 27-million-year periodicity in mass extinctions, integrating recent paleontological data and outer solar system dynamics.

Contribution

It offers a renewed analysis of the Planet X model, linking it to both extinction cycles and recent discoveries of trans-Neptunian objects.

Findings

Confirmation of 27 Myr extinction periodicity in modern data

Challenges to alternative astronomical models based on period and phase

Support for the Planet X model from outer solar system evidence

Abstract

The 27 Myr periodicity in the fossil extinction record has been confirmed in modern data bases dating back 500 Myr, which is twice the time interval of the original analysis from thirty years ago. The surprising regularity of this period has been used to reject the Nemesis model. A second model based on the sun's vertical galactic oscillations has been challenged on the basis of an inconsistency in period and phasing. The third astronomical model originally proposed to explain the periodicity is the Planet X model in which the period is associated with the perihelion precession of the inclined orbit of a trans-Neptunian planet. Recently, and unrelated to mass extinctions, a trans-Neptunian super-Earth planet has been proposed to explain the observation that the inner Oort cloud objects Sedna and 2012VP113 have perihelia that lie near the ecliptic plane. In this Letter we reconsider the Planet X model in light of the confluence of the modern palaeontological and outer solar system dynamical evidence.