May 26, 2014
Chelyabinsk Meteor Collided With Asteroid Before Hitting Earth
Lawrence LeBlond for redOrbit.com - Your Universe Online
A wealth of research has come following the Chelyabinsk meteor that exploded over Russia’s Ural Mountains on February 15, 2013. The latest study, which comes from scientists at the University of Tohoku in Japan, claims that the meteor collided with an asteroid before heading on its collision course with Earth.Analysis of a mineral called jadeite found embedded in fragments recovered after the explosion show that the parent body of the meteor had collided with a larger asteroid of at least 492 feet wide and at a relative speed of 3,000 mph.
"This impact might have separated the Chelyabinsk asteroid from its parent body and delivered it to the Earth," wrote lead author Shin Ozawa, whose research is published in the journal Scientific Reports.
The 2013 explosion is known as the second largest asteroid airburst in human history. The research team noted that this discovery is expected to give scientists more insight into how asteroids may end up on a collision course with Earth in the first place.
It may be of concern that space rocks out there that are known to not be on Earth trajectories now could eventually hit Earth if they do encounter other asteroids in space. However, the scientists believe the Chelyabinsk rock had its collision around 290 million years ago.
Jadeite is only formed under extreme pressure and high temperatures. The jadeite found in the Chelyabinsk meteorite fragments was formed under pressures of at least three to 12 gigapascals during a shock that was longer than 70 milliseconds, reports Brid-Aine Parnell at Forbes.com.
Scientists are still analyzing the fragments of the Chelyabinsk meteor and calculating its path toward Earth as precisely as possible.
A paper published in the journal Science last November provided details on the rock’s path, stating then that the meteor likely had broken off from a larger body before entering Earth’s atmosphere.
In a statement to Reuters, Ozawa described the Chelyabinsk meteor as “a unique sample.”
"It is a near-Earth object that actually hit the Earth, and its trajectory was well-recorded,” Ozawa wrote.
If the Earth was ever to be hit by a larger near-Earth object (NEO), it is likely to be because it was knocked off its course, either by colliding with another space rock or by gravitational forces caused by other cosmic bodies.
The residents of the Ural Mountains region were lucky as the Chelyabinsk meteor exploded high in the atmosphere, leaving just fragments of the meteorite to rain down. The explosion itself sent a shockwave that shattered thousands of windows and left more than 1,000 people with injuries. If the largest event known in human history – the 1908 Tunguska event – were to occur over a more-populated region such as Chelyabinsk, the outcome would have been far worse.
The Tunguska asteroid exploded with a force about 1,000 times more powerful than the Hiroshima atomic bomb, leveling 80 million trees over more than 770 square miles in northern Siberia.