Russian Meteor Likely Came from 'Rubble Pile'

A new study of the fireball that exploded over Russia earlier this year reveals the visitor from space was something of an average Joe when it comes to space rocks.

The largest meteorite strike since the Tunguska event of 1908, February's event belonged to the most common type of meteorite, known as an "ordinary chondrite."

The team of researchers was also able to use videos of the event to determine that the fireball entered Earth's atmosphere at just a little more than 19 kilometers per second.

"Our goal was to understand all circumstances that resulted in the damaging shock wave that sent over 1200 people to hospitals in the Chelyabinsk blast area that day," Peter Jenniskens, a Search for Extraterrestrial Intelligence (SETI) meteor astronomer, said in a statement.

The meteor's brightness peaked at an altitude of just under 30 kilometers, appearing brighter than the Sun and causing some severe sunburns. The team, which also included researchers from the Russian Academy of Sciences, NASA and the University of California, estimated that at that point, three-quarters of the meteoroid had evaporated. The resulting dust cloud was so hot it glowed orange.

Members of the team visited more than 50 villages in the area of the explosion, determining that the shockwave triggered damage about 90 kilometers on either side of its trajectory. A variety of tests, including a chemical and isotopic analysis, placed the object around 4,452 million years old.

Jenniskens posits that it once belonged to a larger "rubble pile" asteroid that broke apart some 1.2 million years ago, with the remaining bits and pieces possibly floating around as near-earth asteroids.

A thorough analysis of the Chelyabinsk event is key in protecting against future events like it, argues Qing-Zhu Yin, a professor from the University of California, Davis. 

"If humanity does not want to go the way of the dinosaurs," he said, "we need to study an event like this in detail."