Earth"s ancient ring may have caused global cooling after asteroid impact

Over 450 million years ago, during a period of intense meteorite bombardment known as the Ordovician impact spike, Earth may have briefly possessed a ring system similar to that of Saturn. Researchers analyzed 21 asteroid craters located in a narrow equatorial band, which is unusual given that only 30% of the land area was near the equator at that time. This concentration of impacts suggests a significant cosmic event, likely a large asteroid that broke apart due to tidal forces, forming a debris ring around the planet. The debris from this ring is believed to have gradually fallen to Earth, leading to an increase in meteorite impacts recorded in geological history. Sedimentary rock layers from this period show extraordinary amounts of meteorite debris, supporting the hypothesis of a ring system. The study highlights how the distribution of impact craters aligns with the theory of a debris ring, which decayed over millions of years. Additionally, scientists speculate that this ring may have cast a shadow on Earth, potentially contributing to a significant global cooling event known as the Hirnantian Icehouse. This cooling occurred during a time when carbon dioxide levels were high, creating a puzzling climate scenario. The ring's ability to block sunlight could have had profound implications for Earth's climate during this period. The findings of this study, published in Earth and Planetary Science Letters, provide new insights into how cosmic events can influence Earth's climate and geological history. The researchers estimate the probability of such a unique impact distribution occurring randomly at 1 in 25 million, underscoring the significance of their findings.