Mass extinctions linked to 27-million-year cycle

A New York University geologist, Professor Michael Rampino, claims Earth's mass extinctions and major geological events follow a 27-million-year cycle tied to the solar system's movement through the Milky Way. Analyzing 89 events over 260 million years, including asteroid impacts and volcanic eruptions, his study in Evolving Earth suggests Earth may be due for another such event. The theory, first proposed in the 1980s, was previously dismissed but now gains new evidence.