Scientists studying the fragments of the Chelyabinsk meteorite have concluded that the object was separated from its parent body after being struck by an asteroid — an impact that ultimately caused it to head towards Earth. Scarily, its sister objects could still be out there.
When Chelyabinsk arrived on February 13, 2013, it quickly became a brilliant superbolide meteor over the southern Ural region of Russia; it's the second largest asteroid airburst in our recorded history. Because of its enormous velocity and shallow atmospheric entry angle, the object exploded, raining down small fragmentary meteorites.
These pieces are now being studied by a team of researchers who are seeking to understand the nature and formational history of near-Earth objects (NEOs). What they're finding is consistent with the going theory: Asteroid-on-asteroid action is a key process in orbital evolution.
(Ozawa et. al | Nature)
After discovering the existence of high-pressure mineral jadeite in the shock-melt veins of the Chelyabinsk meteorite, the researchers estimate the parent body to have been about 500 feet (150 meters) in diameter. The Chelyabinsk meteorite itself was about 30 to 60 feet in length. The second asteroid was traveling at about 3,400 miles per hour when it hit the parent object, splintering off the rock that would become the Chelyabinsk meteor. And in fact, there may be other sister asteroids still threatening Earth.
Now it's important to note that this wasn't a recent event. The team thinks it happened about 290 million years ago. But the impact, in addition to creating the object, caused it to move into an orbital resonance about 10 million years ago, which in turn put it into an Earth-crossing orbit.
Read the entire scientific report here.
[ h/t Discover Magazine ]