The Greatest Asteroid Encounters of All Time!

Asteroids are important building blocks of our solar system. When spacecraft study these small worlds, we learn more about how our neighborhood was formed — moons, planets and, of course, our own planet Earth.

June 30, 1908: Space Rock Explosion Over Tunguska, Siberia

On June 30, 1908, a giant fireball exploded over the forests of Tunguska in Siberia. The impact leveled hundreds of miles of forest, and the exact cause is a bit of a mystery. See how it happened in our On This Day in Space video series.