Analyzing a Giant Meteor Blast: Earth More Vulnerable Than We Thought

The 10,000-ton meteor that burst over the Russian city of Chelyabinsk earlier this year at 40,000 miles per hour shocked the inhabitants of the region and left scores of injuries and broken windows in its wake.

But, as reported in explorations now magazine earlier this year the massive scale of the event represented a boon to scientists at Scripps Institution of Oceanography at UC San Diego who monitor earth processes across several disciplines.

And now that information is paying dividends, most recently in a new study published in the journal Nature that describes in detail the size and scale of the colossal fireball, which was approximately 17 meters (55 feet) wide and delivered an explosion estimated to be on par with 500 kilotons of TNT.

The international team of scientists have shown that Earth is vulnerable to being hit with more Chelyabinsk-sized meteors in the future than previously thought.

The Scripps researchers, including Luciana Astiz, Catherine de Groot-Hedlin, Michael Hedlin, and Gabi Laske, contributed to the study by helping to pin down the location and yield of the main explosion.

“During the time of atmospheric nuclear testing much work was done on estimating the size (explosive yield) of a large above-ground test from the seismic surface waves it excited. We drew on this work to estimate the explosive yield of the Chelyabinsk meteor,” said Michael Hedlin, a research geophysicist at Scripps. “We further analyzed the seismic data to estimate where (geographic and altitude) sound energy came from.”

The time of the source of the surface waves was about 84 seconds after the main flash reported by other sensors, said Hedlin, head of the Laboratory for Atmospheric Acoustics at Scripps, one of the institution’s efforts in long-term observations that deliver valuable data for science and society.

“This gave an altitude estimate of 29 kilometers (18 miles),” he said. “All geographic locations we obtained lay close to the ground track of the meteor but slightly to the north.”

The arrival times of secondary sonic booms heard on videos were also used to locate fragmentation points, and to calculate that the asteroid broke into small pieces between around 30 and 45 kilometers (18.6 and 27.9 miles) above the ground. At peak brightness, the bursting meteor appeared to be 30 times brighter than the sun.

The research team, which included the University of Western Ontario’s Peter Brown, Margaret Campbell-Brown, Paul Wiegert and David Clark, showed that existing models for estimating airburst damage for the circumstances of the Chelyabinsk impact do not match observations. They suggest that the number of objects with diameters in the range of tens of meters that impact the Earth may be several times greater than previously thought.

“Existing models predict events like the Chelyabinsk asteroid might hit every 120 or 150 years, but our data shows the frequency may be closer to every 30 or 40 years,” said Peter Brown. “That’s a big surprise. When Chelyabinsk happened, I would have never expected to see an event big enough to cause damage on the ground. It’s totally outside the realm of what we thought likely in our lifetimes based on earlier statistics. Our statistics now suggest this type of event likely happens with more frequency.”

According to the study, the orbit of the Chelyabinsk asteroid seems to be similar to another asteroid that has orbited close to Earth – the near-Earth asteroid 86039 (199 NC43) – suggesting that the two were probably once part of the same object.

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6 thoughts on “Analyzing a Giant Meteor Blast: Earth More Vulnerable Than We Thought”

  1. I often wondered if Chelyabinsk meteor, aka, super bolide wasn’t part of a bigger space object. It comes as no surprise that scientists now believe it was part of asteroid 86039. I have a theory, that man mostly picks up larger objects was negates or ignores smaller object like the relatively puny likes of Chelyabinsk which might be clustered in packs around much larger asteroids.

  2. In this present times Earth is indeed vulnerable and we may not be as safe as we thought. This is an alarming issue because danger is no longer a thief in the night or fatalities but it can now fall from the skies and lay waste to precious Earth and her inhabitants, humanity can be facing an unprecedented threat but this so called predictions can however minimize loses. Things will be a lot easier if we are faced with a known , we can therefore prepare ourselves for the impact. These researchers are doing an amazing good because their findings and predictions can save lives by evacuating areas and plan damage control for where the events will take place. While scientists are working at their best this is something they cannot prevent from happening, even the Chelyabinsk asteroid evaded detection. This makes me wonder if Earth will be safe in the future, and even more scary; are we really alone in this universe. Meteors can only be the start of unearthly invasions. Just when we thought global warming and pollution was bad we now get meteors. I believe that scientists do have a plan the our planets future and as danger presents itself more frequently these days they may help us survive.Keep it up fellow geniuses!!!!!

  3. It is interesting to see how technology can give us accurate estimates as to how and where the Chelyabinsk asteroid exploded. About a hundred years ago this was not possible, as is the case with the Tunkuska event. In 1908 there was a large explosion in Siberia that was speculated to be caused by an asteroid, and the only event of its type that was witnessed by humans (science@nasa: 2008). According to Don Yeomans, most scientists agree that an asteroid of about 120 feet in diameter detonated in the atmosphere because of the immense heat produced by air friction (science@nasa: 2008). This asteroid was more than twice the size of the Chelyabinsk asteroid, but there were no known casualties (science@nasa: 2008). The explosion of the Tunguska asteroid had a profound effect on the world of science.

    Back in 2008, Yeoman stated that he was not worried about a similar event occuring in the future (science@nasa: 2008). With this statement in mind, it is ironic that, even with the benefits of modern science, the Chelyabinsk asteroid managed to evade detection as it shocked the world.

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