The asteroid that exploded over Chelyabinsk, Russia, in February 2013 experienced an intense collision with another asteroid before hitting Earth. The research is published in Scientific Reports this week.
Shin Ozawa and colleagues analysed fragments of the Chelyabinsk asteroid and report the presence of high-pressure mineral jadeite embedded in glass materials in its shock-melt veins in which high pressure and high temperature conditions can be achieved simultaneously under shock. The mineral composition and the calculated solidification time of the shock-melt veins suggest that a parent body of the asteroid collided with another asteroid of at least 150 metres in diameter at a speed of at least 0.4?1.5 km/s. This impact might have occurred around or after 290 million years ago. The asteroid impact near Chelyabinsk is the second largest airburst recorded on Earth. Thus, understanding the impact history of the Chelyabinsk parent body could help to clarify our knowledge of the formation and evolution processes of near-Earth objects (asteroids and comets that might potentially hit the Earth).