Latest News About How Big Was The Asteroid That Killed Dinosaurs

Direct answer: Most scientists estimate the asteroid that helped cause the dinosaur extinction was about 10–15 kilometers (6–9 miles) in diameter, and it created the Chicxulub crater roughly 180 kilometers (112 miles) across. This is the prevailing consensus based on multiple lines of evidence.

Latest context you asked for:

• The Chicxulub impact is tied to the K–Pg (Cretaceous–Paleogene) extinction event about 66 million years ago, and the size range (10–15 km) comes from crater estimates, global ejecta, and geological dating. If you’d like, I can summarize the key evidence behind these estimates (crater dimensions, ejecta layer, and isotope signatures) in a quick bullet list.[9]
• Some sources sometimes present slightly broader ranges (e.g., 9–12 km) due to uncertainties in modeling the impact and crater formation, but the 10–15 km band is common in modern reviews. Britannica’s 2026 update reflects the 10–15 km range and notes the crater’s ~180 km diameter.[9]
• Recent work has explored the asteroid’s origin and implications for planetary defense, including studies using noble metals like ruthenium to trace the asteroid’s source, which helps contextualize its trajectory and composition. If you want, I can pull a brief update on that line of research.[8]

Would you like a concise timeline of the evidence leading to the 10–15 km size conclusion, or a quick explainer of how scientists infer crater size from the Chicxulub structure? I can also provide sources for further reading.[3][9]