An early morning surprise
On February 15th, 2013, the Russian city Chelyabinsk got the surprise of a lifetime when an asteroid hurtled down through the atmosphere, disintegrating into thousands of pieces that rained down on the ground. Amateur videos from car dashcams—intended to catch insurance frauds—instead captured a glowing fireball streaking across the sky. Reports indicate that at its peak, the object hurtling towards Earth was brighter than the sun. A great thundering sound was heard soon afterwards, and witnesses in the area said that the air of the city smelled like gunpowder.
The event garnered immediate worldwide attention and social media sites erupted at the news. Initial reactions were skeptical for the most part since meteors rarely have a significant effect on the ground, given that most fully disintegrate on their descent. After confirmation by the Russian government, however, the meteor became the hottest story of the day. Videos from Russian citizens’ dashcams of the meteor made their way to Youtube, cultivating millions of views in a matter of hours.
There were a number of injuries sustained by the local population, though very little resulted from the debris. Nearly 1,500 people sought medical attention in Chelyabinsk, and this number included over 300 children. Though most the injuries were minor, there were several reports of residents being hospitalized with significant injuries, though all were expected to survive.
One of the largest causes of injury was curiosity—as the meteor brightened up the sky with its fiery light, people flocked to windows to get a better look. Unfortunately, windows are one of the most dangerous places to be in the event of an external explosion, since the force will blow back the glass into the faces of the onlookers. As a result, many people were hurt by falling shattered windows and glass, resulting in cuts and bruises. The meteor also shut down the local infrastructure, closing down government buildings alongside private businesses to bring the area to a grinding halt.
There was also serious damage sustained by residential and business buildings, schools and even hospitals, leaving thousands of citizens homeless following the blast. Most of these structures were not hit directly by the debris, but instead became damaged as a result of the shock wave. To this day, only a fraction of the repairs have occurred, leaving Chelyabinsk in a lurch in the aftermath.
Though the effects of meteor were disastrous, it was fortunate that it came into contact with a relatively isolated and low-populated area. Had the meteor come near a high-density region, such as New York City or Beijing, the effects would be catastrophic due to the high rises and skyscrapers, and deaths would have been a near certainty.
So, what kind of meteor was it, and why did it cause so much damage?
According to researchers, the Chelyabinsk meteor was the most powerful in over a 100 years, dating back to the Tunguska meteor from 1908. Calculations of the meteor range between research centers, but the average shows that the meteor was approximately 50 feet wide and weighed around 7,000 tons, or the weight of two large vehicles when it first broke through the earth’s atmosphere.
The majority of the meteor’s damage did not come from impact, as the pieces that fell were relatively small. Rather, the culprit was a series of shockwaves resulting from several explosions that occurred as the asteroid broke up in the atmosphere.
According to the Russian Geographical Society, the Chelyabinsk meteor created three blasts of varying power. The first explosion occurred around 60km above sea level and was the most powerful. The explosion was preceded by a bright flash, which lasted about five seconds, and estimates of the explosive power average around 500 kilotons. For comparison, the nuclear blast that devastated Hiroshima during World War II was approximately 13 kilotons, making the power of the blast commensurate with that of a small fusion bomb.
The asteroid itself was likely a stray originating from the asteroid belt, the famous region containing hundreds of thousands of asteroids located between Mars and Jupiter. An analysis of the meteor’s contents revealed that it was a rocky meteor composed of a relatively low iron content, and “was made of material that had been partially melted and recrystallized from the dust and gas cloud of the early solar nebulas”, according to nature.com.
Part of the reason the asteroid exploded in the first place was likely due to its fragile body. Instead of being a dense, solid, study object, the asteroid contained many internal cracks that allowed it to explode into thousands of fragments under the intense pressure of hurtling through earth’s atmosphere. Researchers have theorized that the asteroid may have come into close contact with other celestial bodies, causing damage inside of the object before it collided with Earth.
Most research centers on the lookout for asteroids can only detect meteors that are over 100 meters in size—this gives telescopes the ability to examine large enough reflections of light to determine the presence of a foreign object. The Chelyabinsk meteor, on the other hand, was only around 15 meters and dark in color, making it virtually impossible to identify ahead of time, and so it was able to fly into the atmosphere under the radar.
Could we have seen it coming?
The damage of the Chelyabinsk meteor has hit a nerve, however, as it exposed the holes in current technology and renewed calls for an increased priority given to detecting foreign, celestial objects. At issue is funding, however, and at a NASA funding hearing following the event scientists could not reassure members of Congress that they could stop a potentially devastating asteroid without an increased budget to pay for the necessary technological advances. Their testimony prompted Rep. Lamar Smith to say, “We need to find ways to fund NASA’s projects.”
And the funding is needed. Due to its speed combined with the meteor’s size, current centers—if they could detect the asteroid at all—would only have a day or two at the most to provide a warning, which may not be enough time to properly evacuate regions like Siberia, and definitely not enough time for a large metropolitan area such as London.