Catastrophic Comet Explosion Over Earth 12,800 Years Ago Potentially Initiated Centuries of Severe Cold

In a groundbreaking study published in the journal PLOS One, scientists have discovered evidence of a comet explosion that occurred 12,800 years ago. The research, led by Kirsten E. Zawadzki, James A. Rodman, Heather M. White, and a team of researchers from the University of Massachusetts Amherst, analysed seafloor mud from Baffin Bay, near Greenland.

The study supports the Younger Dryas impact hypothesis (YDIH), suggesting that Earth's encounter with a large comet and its debris trail led to major climatic and environmental changes. The results mirror findings on land across several continents, including the discovery of platinum, iridium, meltglass, nanodiamonds, fractured quartz, and unusual metallic grains containing high levels of nickel, cobalt, platinum, and iridium.

From the four cores retrieved from Baffin Bay, the researchers found layers that matched the Younger Dryas period by radiocarbon dating. They also discovered tiny spheres of melted rock, or microspherules, that appeared to have formed when Earth materials fused with a small amount of alien dust during an airburst explosion.

Other nanoparticles found resemble twisted, deformed metallic droplets, suggesting extreme heat and pressure from a cosmic blast. Some iron particles showed very little oxygen but a lot of nickel, a chemical signature common in comets and meteorites.

The consistency between land and ocean sites strengthens the case that the Younger Dryas cooling was sudden, global, and potentially caused by a fragmented comet. The amount of comet dust in the atmosphere was enough to cause a short-term 'impact winter,' followed by a 1,400-year cooling period, according to one of the study authors, Vladimir Tselmovich.

The study authors note that microspherules are geochemically most similar to terrestrial sediments with traces of extraterrestrial material. The scientists used several advanced techniques, including electron microscopes, spectroscopy, and mass spectrometry, to hunt for extraterrestrial fingerprints in the sediment cores.

The discovery could reframe one of the biggest climate mysteries of the past, linking the Younger Dryas to a comet airburst. The haze of comet dust swirling into the upper atmosphere would have dimmed the sun, causing temperatures to plunge, plants to wither, and the balance of warming at the end of the Ice Age to stall. This could potentially explain the disappearance of mammoths and other giant animals in North America, and the decline of the ancient Paleo-Indian culture.

Further studies are needed, including examining cores from other ocean sites, to confirm the evidence and understand the full extent of the comet's impact on Earth.