Earth’s Big Disasters Might Follow a 27.5-Million-Year Rhythm
A new analysis revisiting 89 major geological events over the past 260 million years finds a dominant roughly 27.5‑million‑year cycle linking Earth’s mass extinctions, large volcanic events, and ocean/sea‑level shifts, with a secondary ~8.9‑million‑year cycle. The study suggests multiple Earth systems may periodically respond to shared long‑term processes (potentially involving mantle convection, orbital cycles, or even solar system galactic movements), rather than random catastrophes. However, the cycle is controversial and not yet proven, with researchers cautioning against inferring direct causality and noting uncertainties in ancient dating and statistical methods.