extinctions

The revolution started with a bang in 1980. For some, this revolution became a religion, even an orthodoxy. The true believers became proselytes and began to see signs supporting their viewpoint everywhere. But each time the proselytes claimed to have found yet another example in support of their “religion,” naysayers and doubters emerged. Two sides formed, each loudly castigating and questioning their opponents.

This back-and-forth ideological debate describes both the historical and still-ongoing struggle over a purported cause of mass extinctions: the meteor impact theory.

At the close of the Permian, 252 million years ago, conditions on Earth took a turn for the worse, nearly wiping out life on land and at sea in the planet’s most severe extinction event. Now, eons later, geologists are implicating a coal seam that dates to the “Great Dying” at the Permian-Triassic boundary in one of the modern world’s worst cancer epidemics.

What the planet’s past mass extinctions tell us about the future of life on Earth

The crash-landing of a 10-kilometer-wide asteroid 65 million years ago made for a very bad day for dinosaurs — or one very lucky day for mammals.

Fires from a comet shower may have killed off the big game in North America about 13,000 years ago, scientists say. Those extinctions have long been attributed either to an abrupt return to glaciation known as the Younger Dryas event or to over-hunting. But now, a team of scientists has found tiny, nanoparticle-sized diamonds in sediments from the Younger Dryas — signs that a cosmic impact may have ultimately been behind both the cold period and the extinctions.