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.

After a massive extinction, diverse marsupials came to dominate this isolated continent.

Some 250 million years ago, some of the largest, most dangerous reptiles ruled this land.

Fossils reveal how life’s explosion in the ocean was recreated on dry land.

Australia’s ancient landscape holds clues to Earth's early history and the beginning of life.

We know more about the Earth now than ever before, but that knowledge is in jeopardy as many Earth-observing satellites are nearing the end of their lives.

What makes a person walk into a theater or a church or a classroom full of students and open fire? What combination of circumstances compels a human being to commit the most inhuman of crimes? Can science in any way help us understand these horrific events and provide any clues as to how to prevent them in the future?

Produced, edited, and animated by Anna Rothschild Production Assistant Allison Eck Special Thanks Stefanie Kaiser Original Footage © WGBH Educational Foundation 2013 ADDITIONAL MEDIA CREDITS (Ceratothoa sp in Blacktail) Host: Diplodus sargus sargus (common names: blacktail or white seabream) Locality: Tsitsikamma National Park, Eastern Cape, South Africa © Nico Smit

The Vikings didn’t invent crucible steel, so where did it come from? Many experts believe that the Volga trade route supplied Vikings with prized crucible steel from the Middle East, where people were more practiced in the art of forging it.

Hurricane Sandy was born just like any other tropical storm: the warm water acts as a “heat engine,” and produces strong winds. But an unfortunate turn catapulted Sandy into the Northeast—making it unusually devastating for those living on or near the coast.

Military historian Mike Loades explores the weapons that the ancient Egyptians used in war. Then, he takes them on a one-of-a-kind chariot ride.

Protective armor was a necessity in Egyptian chariot warfare. Military historian Mike Loades explains what made it so strong.

While testing Curiosity’s parachute in the world’s largest wind tunnel, JPL scientists and engineers were confounded by a failed trial run. The parachute had never failed to open in the past, so why this strange anomaly? By replicating the error and analyzing it in high-resolution footage, they were able to pinpoint the problem.

An innovative computer-based handwriting analysis technique helps NOVA dig deeper into the kidnapping of Charles Lindbergh’s baby. But while the results might sway investigators in a certain direction, they certainly aren’t definitive.

A University of Pennsylvania lab is developing tiny drones that sense their environment.

An engineer describes the next-generation surveillance sensor for UAVs, called ARGUS.

A DARPA researcher describes what would constitute a breakthrough in UAV autonomy.

The X-47B prototype can land on a flight deck without input from a pilot.

A UAV pilot describes what it’s like to conduct a drone strike.

Until recently, scientists have encountered scant evidence of Neanderthal ritual or religious practice. A new discovery, though, suggests that Neanderthals—much like today’s bear hunters—ceremoniously cut off panther paws and kept them as trophies.