Scientists studying ancient sediments in the eastern United States have reported signs of a comet exploding in Earth’s skies 12,800 years ago, potentially causing a thousand-year cold spell known as the Younger Dryas. A new study has strengthened this case by analyzing seafloor mud from Baffin Bay, near Greenland, and found tiny traces of comet dust and metallic debris consistent with a cosmic airburst.
Researchers from the University of South Carolina analyzed four sediment cores retrieved from Baffin Bay, which matched the Younger Dryas period through radiocarbon dating. They used advanced techniques such as electron microscopes and spectroscopy to identify microscopic particles that exhibited chemical signatures common in comets and meteorites.
The study’s findings include metallic grains containing high levels of nickel, cobalt, platinum, and iridium, as well as tiny spheres of melted rock known as microspherules. These discoveries mirror what other studies have found on land across several continents, suggesting a fragmented comet that shattered in the skies may have caused the Younger Dryas cooling.
The study’s authors suggest that the comet dust haze scattered sunlight back into space, plunging temperatures and causing plants to wither. The findings support the Younger Dryas impact hypothesis, which proposes that Earth’s encounter with a large comet led to major climatic and environmental changes.
However, the researchers acknowledge that the evidence is not yet complete, particularly the absence of a crater. They plan to examine cores from other ocean sites to see if the signs of comet dust appear there as well, in order to further support or refute the comet impact theory for the Younger Dryas event.
Source: https://www.zmescience.com/science/news-science/comet-hit-earth-12800-years-ago