Massive comet trail may have transformed Earth's climate more than 12,000 years ago, tiny particles suggest

A four-paneled image with microscope images of metallic dust.

Scientists have found new evidence that a massive comet trail may have caused climate upheaval on Earth more than 12,000 years ago.

Tiny particles detected in ocean sediment cores suggest that dust from a large, disintegrating comet entered Earth's atmosphere around the beginning of the Younger Dryas event, a period of abrupt cooling that caused temperatures in the Northern Hemisphere to plummet by up to 18 degrees Fahrenheit (10 degrees Celsius) within about a year. The researchers shared their findings Aug. 6 in the journal PLOS One.