New research adds weight to the idea that the dinosaur extinction was triggered by a cosmic impact, and the findings suggest more than one asteroid was involved. A study led by researchers at Heriot-Watt University presents evidence of a second space rock colliding with Earth around 66 million years ago. This second body is estimated to have been about 500 meters in diameter and is believed to have slammed into the crust near what is now the coastline of the Republic of Guinea in West Africa. The combined chaos from two major impacts would have amplified environmental stresses during that critical interval, helping to explain anomalies that a single-hit scenario cannot fully account for. The work also complements the well-established record surrounding the Cretaceous–Paleogene boundary, where chemical signatures and geological clues have long hinted at a more complex catastrophe. By weaving together geological, geophysical, and paleontological data, the researchers sketch a more complete story of how multiple atmospheric and surface phenomena could have disrupted ecosystems across the globe.
The first signal of a second impact was documented in 2022, and recent high‑resolution 3D seismic imaging has revealed a subsurface depression about nine kilometers deep that aligns with a second crater. The newly mapped structure sits in a coastal-to-near-coastal setting that would have placed the impact in a shallow marine to near‑shore environment at the relevant time. This depression strongly supports the interpretation that a buried impact site exists, consistent with a scenario in which two large bodies struck Earth in close succession and together reshaped the planet’s surface record.
According to Dr. Nicholson, the asteroid approached from the northeast at an incidence angle between 20 and 40 degrees and would have entered the atmosphere at an estimated speed around 72,000 kilometers per hour. The combination of direction, angle, and velocity helps explain how the energy released at impact could have formed a sizeable crater and contributed to the global environmental upheaval associated with the mass extinction. These numbers emerge from models that simulate crater formation and energy transfer during atmospheric entry, underscoring the plausibility of a dual‑impact event shaping Earth’s late Cretaceous history.
In a separate line of inquiry, American scientists identified an ancient seabed located more than 400 kilometers beneath the Earth’s surface. The discovery points to compression within the mantle driven by subduction, the process by which one tectonic plate sinks beneath another and gradually restructures the planet’s interior over geologic time. This deep geological signal provides important context for understanding how Earth’s outer layers responded to catastrophic external impacts and how such forces interact with internal tectonic processes.
Earlier discussions by researchers dismissed rumors of a second moon approaching Earth. The newer evidence strengthens the case for a more complex late‑Cretaceous scenario, in which multiple large bodies could have contributed to the dramatic extinction event. It also demonstrates how modern geophysical techniques can uncover hidden chapters in Earth’s deep past, offering fresh insights into the forces that have shaped our planet’s history and the life it supports.