A blinding flash of light streaked across the Russian sky, followed by a shuddering blast strong enough to damage buildings and send more than 1,000 people to the hospital. On the morning of February 15, 2013, a 7,000-ton asteroid crashed into the Earth's atmosphere. According to NASA, the Siberian meteor exploded with the power of 30 Hiroshima bombs and was the largest object to burst in the atmosphere since the Tunguska event of 1908, which was also in Siberia and left few eyewitnesses or clues. This time, the event was captured by digital dashboard cameras, now common in Russian autos and trucks. Within days, NOVA crews joined impact scientists in Russia as they hunted for clues about the meteor's origin and makeup. From their findings, it's clear we came close to a far worse disaster, which NOVA sets in perspective by looking at greater explosions from the past, including Tunguska and the asteroid that wiped out the dinosaurs 65 million years ago. "Meteor Strike" asks: Is our solar system a deadly celestial shooting gallery with Earth in the crosshairs? And what are the chances that another, more massive asteroid is heading straight for us?