Lifeboat Foundation

When the Chicxulub impactor, a six-mile-wide asteroid, struck Earth 66 million years ago, the dinosaurs had no warning.

If an asteroid that size hit Earth today, a shock wave two million times more powerful than a hydrogen bomb would flatten forests and trigger tsunamis. A seismic pulse equal to a magnitude 10 earthquake would crumble cities.

And long after the impact, a cloud of hot dust, ash, and steam would blot out the sun, plunging the Earth into freezing cold.