What happens when a space rock hits Earth?
Simulate what happens when an asteroid strikes Earth — calculate the crater size, energy release, thermal radiation zone, seismic effects, and the scale of devastation based on impactor size, composition, and velocity. Set the asteroid's diameter, density, impact velocity, and target surface, then see the full impact scenario including global vs. local effects and historical comparisons.
💡 The Chicxulub impactor that killed the dinosaurs was roughly 10–15 km wide and released energy equivalent to one billion atomic bombs.
Impact energy is calculated as one half times mass times velocity squared, then converted to TNT equivalent (1 megaton = 4.184 × 10^15 joules). Mass is derived from diameter and density (typical rocky asteroid density is ~3,000 kg/m³, iron is ~7,800 kg/m³). The simulator uses the same scaling laws published by Collins, Melosh and Marcus that power Purdue University's Earth Impact Effects Program.
The Chicxulub impactor was roughly 10–15 km in diameter and struck what is now Mexico's Yucatán Peninsula 66 million years ago. It released about 100 million megatons of TNT — roughly two million times more powerful than the largest nuclear weapon ever tested. The resulting crater is about 180 km wide.
An asteroid as small as 50–100 metres across, like the one suspected of causing the 1908 Tunguska airburst, can flatten a metropolitan area. The Tunguska event released about 10–15 megatons and destroyed 2,000 km² of Siberian forest. A 1 km asteroid would cause regional devastation; a 10 km impactor threatens global civilization.
Tunguska-scale (~50 m) impacts happen roughly once per 200–300 years. City-killer (~140 m) impacts occur about once per 20,000 years. Continental-scale (~1 km) impacts strike about once every 500,000 years, and dinosaur-killer (~10 km) impacts happen on roughly 100-million-year timescales. NASA's planetary defence programme tracks every known near-Earth object larger than 140 metres.
Yes — NASA's DART mission proved kinetic deflection in 2022 by altering the orbit of asteroid Dimorphos. Other proposed methods include gravity tractors, ion-beam shepherding and, as a last resort, nuclear stand-off detonations. With 10+ years of warning, even small velocity changes (a few cm/s) are enough to make an asteroid miss Earth.