Q&A with David Goldberg: The Meteor Strike in Russia's Chelyabinsk Region
The Office of University Communications
February 19, 2013
It’s not every day that a meteor slams into the Earth. But on February 15, that's exactly what happened in central Russia, as a meteor crashed through the atmosphere, injuring more than 1,000 people and causing damage in several cities. To find out more about this amazing event, DrexelNow spoke with David Goldberg, a professor and director of Undergraduate Studies in the Department of Physics who specializes in theoretical cosmology and astrophysics.
Generally speaking, what are your thoughts about this meteor strike and the damage it caused?
This was a staggering and dramatic event—made all the more so as it took place over a populated area. A surprising number of people had their cameras running for other reasons, which means that we've seen the meteor from lots of perspectives. There were shattered windows, other structural damage and at last count over 1,000 reported injuries. Fortunately, no deaths have been reported.
Do you think there is a connection between Friday’s meteor strike and Russian news reports that the Asteroid 2012 DA14 was to make the closest recorded pass of an asteroid (about 17,150 miles)?
Dr. David Goldberg
People tend to forget how mind-bogglingly fast things are moving through space. Even though the meteor strike and the asteroid seem fairly closely timed, they aren't. To put things in perspective, the Russian meteoroid was moving at least 11 km/s (nearly 25,000 mph—and possibly faster), and hit at roughly 10:15 p.m. EST. The Asteroid DA14 didn't pass by Earth until 2:30 p.m. the next day, 16 hours later. A rough estimate puts them at least 400,000 miles away from one another. What's more, if they were related, we'd expect a large number of meteor strikes (as opposed to only one) as the asteroid was pulled apart by tidal effects from Earth's gravity.
Could this meteor strike have been predicted/ prevented? How likely is something like this to happen here in the United States? What protection/ prevention methods do we have in the U.S. for something like this?
Likely to happen? Absolutely. The only question is when.
The Russian meteor was about 10 meters across, at an estimated mass of about 10 tons. Events on this scale happen about once a decade, but since most Earth is made up of water, we don't normally notice them. At roughly 3.8 million square miles, the U.S. makes up a little less than two percent of the surface of the planet. So as an approximation, we'll get an event like this in the U.S. every 500 years or so.
It seems unlikely that we'd be able to prevent or even really predict a meteor of this size. In part, that's because until it enters the atmosphere, meteors and other space debris don't create their own light. They just reflect sunlight. The Russian meteor is a few times larger than a bus, and not nearly as reflective. Try to imagine catching the glint off a space-bus millions of miles away as it travels at tens of thousands of miles an hour and you'll get some sense of the difficulty.
On the other hand, the larger the potential impact, generally speaking, the easier it is to see. The objects that could cause real damage to Earth as a whole hit much less frequently, but are much easier to see. An object the size of DA14, for instance, will hit every 1,000 years or so, and obviously, we saw that well in advance of its closest approach—though this required dedicated monitoring. Planetary events can occur on the timescale of tens of millions of years, and while there are large networks that are monitoring “planet killers,” even if we identified an impact ahead of time, we don't currently have a way to prevent them.
It’s said that most meteors burn up in Earth’s atmosphere; why did this one survive?
A lot of it did blow up in the atmosphere. As meteors (technically, they're meteoroids at this point in their life cycle) enter the atmosphere they undergo enormous frictional forces from the air. Remember, the Russian meteor was traveling so fast—more than 30 times the speed of sound—that the loud sound you may have heard on the videos was a sonic boom.
Friction heats fast-moving objects, and since many meteors have water and other materials inside them, this causes the meteors to explode. These explosions can cause much of the damage. The Russian meteor seemed to break up many kilometers above the Earth. I don't know that any of the meteorites (the rocks that actually hit the ground) have even been recovered.
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