Size of the Chicxulub Impact Asteroid

The asteroid that created the Chicxulub crater is estimated to have been about 10 to 15 kilometers (6 to 9 miles) in diameter. This is roughly the size of Mount Everest, but moving at hypersonic speeds. The impact, which occurred approximately 66 million years ago, released an amount of energy equivalent to billions of atomic bombs, creating a crater over 180 kilometers (110 miles) wide and 20 kilometers (12 miles) deep. This catastrophic event is widely accepted as the primary cause of the Cretaceous–Paleogene (K-Pg) extinction event, which wiped out approximately 75% of plant and animal species on Earth, including most dinosaurs.

The impact triggered a chain of devastating global effects, including massive tsunamis, widespread wildfires, and a prolonged 'impact winter' caused by dust and aerosols blocking sunlight, leading to a collapse of the food chain. Evidence for this event includes a global layer of iridium (a rare element on Earth but common in asteroids), shocked quartz, and tektites (glassy spheres formed from molten rock) found in geological strata worldwide, all dated to the same time.

Pro tip: While the asteroid's direct impact was immense, it was the subsequent global environmental changes – specifically the long-term blocking of sunlight and rapid climate shift – that truly led to the mass extinction, rather than just the immediate blast.