This entry is part 3 of 3 in the series Meteor Theme Week

The Chelyabinsk Fireball

This week the newsletter touched on a couple of important points in the study of meteorites. We started with a sharpshooting rock in Benld, Illinois, that left an interesting path to its final resting place in 1938. At the time it was the closest a human had been to a strike in recorded history. Then we jumped ahead to Cold War-era Alabama, where a human being was impacted by a falling space object for the first time in a verified way. Unbelievably, the Sylacauga meteorite did not kill Ann Hodges, but it collided with her life in other, lasting ways.

In the Benld situation, we discussed how important the remaining evidence was to astronomers, as it was the first meteorite that could be probed for information about its arrival. Humans did not have access to cameras or computers, so first-hand knowledge and physical interactions were crucial to understanding these interstellar travelers. As technology improved, we have been able to better document occasions of invasion from space rocks.

We have long been fascinated by shooting stars, and watching meteor showers is a great way to experience the beauty of the universe. But most of those instances are caused by tiny, sand- or pebble-sized particles that burn up quickly in the atmosphere. Sometimes, though, our planet meets larger objects. Think of the asteroid thought to have wiped out the dinosaurs. Despite the ubiquity of cameras in today’s society, catching larger meteors or asteroids on film is still extremely rare. For one, three-quarters of the world is covered by ocean and not populated by people, so most incidents are never recorded by humans or technology. Further, the larger the visitor, the rarer the occasion.

Still, every once in a while, the shooting stars align and things get, shall we say, lit.

Russia is a big place. Roughly one-eighth of all landmass on our planet lies within the country. It is 60% larger than the second-biggest nation, Canada, and that’s after the Soviet Union dissolved. If a big chunk of rock is going to show up over land, odds are it will happen in Russia. And that’s just what transpired in the city and oblast of Chelyabinsk on the morning of 15 February 2013.

Though we will never even be able to estimate the initial size of the Sylacauga meteor, the pieces that hit the ground weighed about 12 pounds. The object that introduced itself to our planet in 2013 over Russia laughs at that measurement. The Chelyabinsk meteor is thought to have been 20 meters in diameter (60 feet) and, according to NASA, probably weighed 11,000 tons. That’s 22,000,000 pounds. For scale, the Eiffel Tower weighs 10,100 tons.

The Chelyabinsk meteor was what astronomers refer to as a fireball, which is defined as a meteor brighter than any of the planets. It was also classified as a bolide, which means it was an exceptionally bright meteor that also exploded. This bad girl was so large that it was even termed a superbolide. To reach that status the object must be 100 times brighter than the moon. In fact, today’s subject blew that threshold away. It was momentarily 30 times as bright as the sun! Some witnesses were flash blinded and others received ultraviolet burns. People could see it 62 miles away.

The rock raced across the sky at a speed of approximately 40,000 miles per hour. The speed of sound is 767 miles per hour. Because of this velocity and the angle of entry, the meteor exploded about 18 miles above sea level, causing an airburst, which sent a shockwave that emanated over 16 miles from its origin.

These statistics are mind-boggling and worthy of inspection on their own, but what makes the Chelyabinsk meteor even more interesting again comes down to Russia. The country is permeated with dash cams. Nearly every automobile is outfitted with one. On that February morning, thousands of humans were driving to jobs and errands, which made this event the best-documented meteor in history.

In the video above you can see a lot of fantastic footage of the fireball. From a distance, it is a beautiful, if terrifying, streak. Those who were closer to the blast, however, must have experienced sheer horror.

Most of the meteor’s energy was absorbed by the atmosphere. One of the many times we can thank air for being filled with molecules instead of simply being empty space. Scientists estimate its pre-blast energy in the range of 26-33 Hiroshima atomic bombs. Though the blast caused panic in Chelyabinsk, the planet was fortunately spared much greater damage because it broke up in the atmosphere. The shock wave was enormous, but the pieces of the meteor that fell to the ground after the explosion were relatively tiny.

1,500 people were injured by the shock wave and 7,200 buildings were substantially damaged. Fortunately, no one perished. Back in July, we explored infrasound, which is sound below the threshold of human hearing. Infrasound waves from the Chelyabinsk fireball were detected as far away as Antarctica, over 9,000 miles away. In fact, the infrasound signature was so large it circled the earth multiple times, taking more than a day to dissipate. To date, the explosion produced the largest set of infrasounds ever recorded by the system set up by the Comprehensive Test Ban Treaty Organization, which monitors nuclear weapon usage.

As if all the preceding information and video weren’t fascinating enough, this event had one more trick up its sleeve.

After the small pieces fell to the ground, residents, especially schoolchildren, rummaged through the snow, digging beneath tiny holes made by falling pieces, to collect souvenirs. Several hours after the impact, people discovered a 20-foot hole in nearby Lake Chebarkul. Although it was not immediately certain a meteorite had caused the disturbance, scientists thought it fairly likely.

By June of 2013, magnetic imaging showed a two-foot meteorite did indeed lie in the mud of the lake. Scientists estimated the chunk might weigh 660 pounds. They worked to bring the space invader to the surface.

In October, the rock was finally raised. When placed on a scale, the device broke into three pieces because the mass was much greater than anticipated: 1,442 pounds!

While it was certainly a great discovery, the coup d’etat was still a month away.

In November 2013, security footage from Lake Chebarkul was discovered to actually show the moment of the impact!

Unfortunately, the video is grainy and the impact is not sensational. Instead, one can see the snow and ice exploding upward after the impact and then left to right. The shard was traveling at 64% the speed of sound, making it very difficult to see with the eye.

In the video, the impact occurs at approximately 41 seconds.

Here’s a breakdown of the footage, which is still difficult to discern, but you can follow the snow and ice well.

Obviously, this video is gnarly, but you might say to yourself, “yes, it’s cool, but what’s the big deal about this little puff of snow and ice?”

The above footage is the first time a direct meteor strike was ever captured on video! We have seen fireballs and showers and streaks, but an actual impact had never before been caught with video evidence. Radical!