You’ve probably heard the theory that an asteroid impact caused the extinction of the dinosaurs tens of millions years ago, but did you know that a similar impact may have caused the extinction of the woolly mammoths, just 12,900 years ago? According to Canada’s Globe and Mail newspaper, a Brown University geologist is a leading researcher into this event…

Researchers studying a dark layer of dirt at 10 sites around North America say they have found evidence that an asteroid or a comet may have killed the woolly mammoths, giant sloths, camels and other huge creatures that once roamed the continent.
The international team of researchers looked under what is known as “black mat” sediment, which dates back to 12,900 years ago. It coincides with a period of abrupt global cooling known as the “Big Freeze,” or the Younger Dryas….
“We don’t have a smoking gun for our theory, but we sure have a lot of shell casings,” said Peter Schultz, a planetary geologist at Brown University in Rhode Island.
“Taken together, the markers found in the samples offer intriguing evidence that North America had a major impact event about 12,900 years ago.”

This news actually makes me feel a little better about the immediate future of humanity.
Scientific evidence has been found in the fossil record indicating a cycle of major worldwide extinction events occurring about every 62 million years or so. Here’s a description of the theory from National Geographic…

Robert Rohde and Richard Muller are vexed. For the past 542 million years the number of animal species living in the world’s oceans has risen and fallen in a repeating pattern, and the scientists haven’t the foggiest idea why….
The pattern includes a rise and fall of marine animal diversity every 62 million years and a weaker cycle of rising and falling marine diversity, which repeats every 140 million years. The researchers think that expanding and retreating glaciers may explain the 140-million-year cycle, but they are stumped over what drives the 62-million-year cycle.
The declines in the 62-million-year cycle correspond with some of the best known mass extinctions on Earth.
Among them are the die-off caused by the asteroid or comet widely believed to have doomed the dinosaurs 65 million years ago and the “Great Dying” of 250 million years ago. During the Great Dying, some unknown cause wiped out most life on Earth.

The extinction of dinosaurs has generally been taken to have been the last event in the 62-million year cycle, meaning another catastrophic extinction may be overdue and ready to begin any day now. Unless, of course, the “scheduled” extinction event (assuming the theories to be true) already happened, 12,900 years ago.
Biologists have generally proposed various one-off explanations, e.g. the rise of humanity, for the set of extinctions that claimed the woolly mammoth. If, however, the extinctions 12,900 years ago were part of the 62-million year cycle that’s connected to various astronomical and climatic factors, we may be safe going forward from today for at least the next 61.99 million years!