Planetary securityChelyabinsk meteor explosion a "wake-up call," scientists warn
Three new studies have revealed details of the meteor that exploded above Russian city, Chelyabinsk, in February this year. Their findings provide information about the meteor’s origin, trajectory, power and damage by the airburst (the shock wave that travelled through the air from the explosion). These findings may help to refine theoretical models about the likely frequency of such events, the potential damage they could cause and hazard mitigation strategies needed for planetary protection.
Three studies have revealed details of the meteor that exploded above Russian city, Chelyabinsk, in February this year.
Their findings, published last week in a pair of papers in Nature and one in Science, provide information about the meteor’s origin, trajectory, power and damage by the airburst (the shock wave that travelled through the air from the explosion).
These findings may help to refine theoretical models about the likely frequency of such events, the potential damage they could cause and hazard mitigation strategies needed for planetary protection.
Trajectory, structure and origin
In the first study, led by Jiri Borovicka from the Astronomical Institute of the Academy of Sciences of the Czech Republic, fifteen videos from eyewitnesses were analysed, most of which were filmed on smartphones and posted to YouTube.
Dr. Borovicka explained that the videos were chosen based on the angles they were filmed and then calibrated for clarity with the help of an engineer.
After the location of each video was tracked down, the sites were photographed during the night.
Using the positions of the stars from the night-time shots, the authors determined the position of the superbolide (extremely bright meteor).
“I am stunned by the amount of detail obtained from analysing smartphone footage,” said Alan Duffy, a theoretical astrophysicist and cosmologist with the University of Melbourne.
“It demonstrates the ingenuity with which the researchers used to tease out information.”
By first reconstructing the path the asteroid took as it entered the Earth’s atmosphere, and then modelling thousands of possible trajectories, the authors determined that the origin of this superbolide likely belonged to the Asteroid Belt that sits between the orbits of Mars and Jupiter.
They also found that the Chelyabinsk asteroid shares a very similar trajectory with the 2.2km-diameter near-Earth asteroid 860389 (also known as 1999 NC43) that had once orbited close to Earth.
This makes it likely that both asteroids once belonged to the same object, with the larger asteroid being the parent of the Chelyabinsk superbolide.
Finally, using the recorded footage of the fragmentation of the superbolide, along with the audio records of the sonic booms that followed, the researchers were able to provide estimates for the likely composition, structural strength and size of the asteroid.
Their best guess is that the object was in fact a fractured stone, in agreement with the collision origin model, roughly measuring nineteen metres across.
