Named after the Hindu god of destruction, the Shiva Hypothesis is a hypothesis that purports to explain an apparent pattern in mass extinctions caused by impact events.
The hypothesis, created by Michael Rampino of New York University, says that gravitational disturbances caused by the Solar System crossing the plane of the Milky Way galaxy are enough to disturb comets in the Oort cloud surrounding the Solar System. This sends comets in towards the inner Solar System, which raises the chance of an impact. According to the hypothesis, this results in the Earth experiencing large impact events about every 30 million years (such as the Cretaceous-Tertiary extinction event).