Earth's Greatest Catastrophes Seem to Follow a Mysterious 27-Million-Year Pulse

A new analysis of 89 major geological events over 260 million years finds stronger evidence for a recurring roughly 27.5-million-year cycle.

The study includes mass extinctions, large volcanic eruptions, ocean anoxia, sea-level shifts, tectonic change, and other major events.

Researchers also see a weaker 8.9-million-year signal and discuss possible drivers such as mantle processes, surface loading, and motion through the Milky Way.

If real, the pattern suggests Earth’s biggest crises may be part of a long-term cycle rather than random events.