On February 15, 2013, a meteoroid exploded over Russia with the energy of an estimated 470 kilotons of TNT, the equivalent of about 30 Hiroshima bombs. The bolide streaked through Russian skies at 9:20 a.m. local time and outshone the Sun. One minute 28 seconds later, shock waves from its deceleration and explosion collapsed structures and blew out roughly 100,000 square meters (1 million square feet) of windows.
The meteoroid exploded almost directly above Chelyabinsk, an industrial city of about 1 million people. More than 1,000 people were injured, mostly by flying glass. This incident is now known as the Chelyabinsk crash. Early reports suggested that a crater was formed on the frozen Lake Chebarkul, about 80 kilometers (50 miles) west of Chelyabinsk, yet it is still unclear whether the fireball and the hole are actually related.
Roughly 16 hours later, another asteroid called 2012 DA14 passed just 27,700 km from the surface of Earth. This is by far the closest known object of this size that has passed by our planet. Important thing to know is that the two meteoroids were moving in different directions and scientists from NASA say they had no relation to one another and that the meteoroid came from the asteroid belt.
The asteroid was moving from south to north, while the bolide east to west. Calculations put the outer end of the impactor’s former orbit in the asteroid as seen below.
An event of this magnitude happens about once per century. It’s the biggest known impact since the Tunguska event in 1908, which exploded with roughly 20 megatons a mere 8.5 km above the ground and flattened 2,000 square kilometers of trees in central Siberia. Thankfully no one was killed by the Chelyabinsk event, but that’s no guarantee for future safety. The one-two combo with 2012 DA14 should serve as a wake-up call, experts say.
Besides the worldwide attention, the event has scientific value. According to scientists the major significance is that this is the first well documented event which has clear ground level effects. This will permit calibration of entry models for tens of meter-sized objects for the first time.
Thus we can say that despite the human hardship, we see a silver lining in this asteroid breakup. The well-documented event, along with the very close 2012 DA14 flyby, serves as a wake-up call that humanity needs to view the asteroid impact threat as something more serious than fodder for mediocre Hollywood action flicks. The event over Russia was big enough that the entire world took notice, but not so large as to wreak death and destruction on a large scale. Every government in the world is now keenly aware that Earth lies amidst a cosmic shooting gallery, and that it’s possible for an asteroid to explode over its territory.
Scientists and astronomers have so far done their part to discover threatening asteroids and characterize the impact hazard. Now it’s time for the international community to come together to take the next logical steps in defending our planet.