10km Asteroid Struck Earth 66 Million Years Ago, Wiping Out About Half of Species
Updated
Updated · The Conversation · May 11
10km Asteroid Struck Earth 66 Million Years Ago, Wiping Out About Half of Species
4 articles · Updated · The Conversation · May 11
A roughly 10km-wide asteroid slammed into shallow seas near today’s Caribbean 66 million years ago, carving a crater about 180km wide and 20km deep and triggering the mass extinction that ended the dinosaurs.
Within minutes, the impact unleashed thermal radiation, supersonic winds, earthquakes and 100-metre megatsunamis; life within 2,000km was likely killed quickly by blast heat, fire or flooding.
Within a week, dust and soot had cut sunlight to about one-thousandth of normal, global temperatures fell at least 5°C, and acid rain with pH near 1 spread as sulfur- and nitrogen-rich gases condensed.
A year later, average surface temperatures were about 15°C lower, more than 50% of plants had died out, and dinosaurs, pterosaurs and many marine groups were gone while only small, adaptable survivors persisted.
Evidence assembled since the 1980 iridium-spike discovery and the 1991 identification of the Chicxulub crater shows the impact reshaped life on Earth, opening ecological space for mammals to expand.
If life recovered 'ridiculously fast' after the asteroid, are modern ecosystems more resilient to catastrophe than we currently believe?
What survival secrets of a newly found hamster-sized mammal helped it outlive the dinosaurs, and what can they teach us today?
The Chicxulub Impact: How a 66-Million-Year-Old Asteroid Shaped Earth's Mass Extinction, Recovery, and Modern Planetary Defense
Overview
Around 66 million years ago, the Chicxulub asteroid struck what is now Mexico’s Yucatán Peninsula, releasing immense energy and leaving a massive crater. This event triggered the Cretaceous-Paleogene (K-Pg) mass extinction, fundamentally reshaping life on Earth. Scientists found a global iridium-enriched layer, supporting an extraterrestrial cause for the extinction. Dinosaur fossils are always found below this layer, reinforcing the timeline of their disappearance. By studying geological signatures and core samples from the crater, researchers continue to unravel how this catastrophic impact led to the extinction of dinosaurs and many other species, opening the way for new life to evolve.