While eyes all over the world eagerly waited for the 2012 DA14 asteroid to make its way past earth, Friday, February 15, 2013, at approximately 9:20 am, Russian time, what is classified as a small asteroid, not a meteor (early estimates guessing about one-third the size of the D14) entered the Earth's atmosphere and broke up over Chelyabinsk, Russia.
With an impact the magnitude of a nuclear explosion, early morning reports of 500 injured had climbed to 1,000 by mid-day. Windows were blown out and walls crumbled, leaving damage to upwards of 3,000 buildings.
Approximately 15 meters in diameter, the small asteroid weighed approximately 300 kilotons. Traveling at 18 kilometers per second, or 40,000 miles per hour, it entered the Earth's atmosphere at a 20 degree penetration, spent about 30 seconds visible in the Earth's atmosphere. The Earth's atmosphere does play a protective role, thus absorbing its energy and slowing its speed until, leaving a trail ten miles long. Then with a series of explosions, with the power of a nuclear explosion, it broke up between 12 and 15 miles above the Earth's surface and fell to the city of Chelyabinsk, Russia. People were out and about and there were many pictures and videos of the its ascent to Earth. Many of the injuries were to people who ran to windows to see what was going on only to be hit by flying glass.
The first question that came to everybody's mind was, whether the D14 asteroid and the meteor that fell in Russia were related. Although it was very unusual that the two would happen in the same day, according to NASA scientists, Bill Cooke and Paul Chodas, they were not related. "The trajectory of the Russia meteor was significantly different than the trajectory of the asteroid." Although data is still being collected, "Analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14's trajectory is in the opposite direction, from south to north."
The next big question was why we didn't see it. First, in comparison to other asteroids, it was not very large, but it was also between the earth and the sun and was not visible in the day sky. They would have seen it coming from the same direction if it had been in the night sky. It came from the asteroid belt and had looped around the sun, probably a year ago. Brighter than the sun, it was coming to us from the direction of the sun. These asteroids are detected optically, not by radar, and was still never seen because at the times when it would have been visible it was daylight in the areas where it would have seen and objects such as this are simply not visible during the day. The telescopes monitor the sky at night, but it was never in line of sight at night, thus was never picked up. It would have taken a craft circling the Earth searching for such objects to have actually seen this one coming. Also, in the scheme of things, this was a relatively small asteroid, and even in the search for asteroids, this one would not have got a lot of notice.
According to Cook though, asteroids pose a bigger problem than anybody realizes and NASA has put funding into both the Meteoroid Environments Office at NASA's Marshall Space Flight Center in Huntsville, Alabama and the Near Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, California to study the problem.
Although every day something like 80 tons of meteorite material enters the Earth's atmosphere, most of that burns up before it hits the Earth. What we do know is that 90% of meteorites that enter the Earth's atmosphere are pretty common, not very interesting, and they do not generate any news at all. Maybe once a day, somebody will find and/or see a basketball size piece that reaches the Earth. In an average month, there will be one the size of a car, found somewhere on Earth. The one that hit Russia was a rare event, a once in a 100 year occurrence. Before this, the last largest meteorite hit on record was known as the 1908 Tunguska Event, when a meteorite hit in Tunguska, Siberia, and what is now Krasnoyarsk Krai, Russia. Although it broke up in the air before it ever hit the Earth, the impact of its blast was about 1,000 times more powerful than the atomic bomb dropped on Hiroshima, Japan. Since then, in 1947, an approximate 70 ton meteorite fell in the Sikhote-Alin Mountains in eastern Siberia. In comparison to the meteor that hit more recently in Indonesia in 2009, this latest one in Russia was four to five times more powerful.
In that these events are similar in impact and magnitude to a nuclear explosion, the international agencies established to monitor nuclear explosions provide the data on them At this point, four agencies in the area have reported an impact. Although they do not know how many at this point, there were several distinct explosions as the asteroid broke up over Chelyabinsk. Scientists do not yet know how far away the blast was felt, more data will come later from the other agencies as well.
With an impact the magnitude of a nuclear explosion, early morning reports of 500 injured had climbed to 1,000 by mid-day. Windows were blown out and walls crumbled, leaving damage to upwards of 3,000 buildings.
Approximately 15 meters in diameter, the small asteroid weighed approximately 300 kilotons. Traveling at 18 kilometers per second, or 40,000 miles per hour, it entered the Earth's atmosphere at a 20 degree penetration, spent about 30 seconds visible in the Earth's atmosphere. The Earth's atmosphere does play a protective role, thus absorbing its energy and slowing its speed until, leaving a trail ten miles long. Then with a series of explosions, with the power of a nuclear explosion, it broke up between 12 and 15 miles above the Earth's surface and fell to the city of Chelyabinsk, Russia. People were out and about and there were many pictures and videos of the its ascent to Earth. Many of the injuries were to people who ran to windows to see what was going on only to be hit by flying glass.
The first question that came to everybody's mind was, whether the D14 asteroid and the meteor that fell in Russia were related. Although it was very unusual that the two would happen in the same day, according to NASA scientists, Bill Cooke and Paul Chodas, they were not related. "The trajectory of the Russia meteor was significantly different than the trajectory of the asteroid." Although data is still being collected, "Analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14's trajectory is in the opposite direction, from south to north."
The next big question was why we didn't see it. First, in comparison to other asteroids, it was not very large, but it was also between the earth and the sun and was not visible in the day sky. They would have seen it coming from the same direction if it had been in the night sky. It came from the asteroid belt and had looped around the sun, probably a year ago. Brighter than the sun, it was coming to us from the direction of the sun. These asteroids are detected optically, not by radar, and was still never seen because at the times when it would have been visible it was daylight in the areas where it would have seen and objects such as this are simply not visible during the day. The telescopes monitor the sky at night, but it was never in line of sight at night, thus was never picked up. It would have taken a craft circling the Earth searching for such objects to have actually seen this one coming. Also, in the scheme of things, this was a relatively small asteroid, and even in the search for asteroids, this one would not have got a lot of notice.
According to Cook though, asteroids pose a bigger problem than anybody realizes and NASA has put funding into both the Meteoroid Environments Office at NASA's Marshall Space Flight Center in Huntsville, Alabama and the Near Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, California to study the problem.
Although every day something like 80 tons of meteorite material enters the Earth's atmosphere, most of that burns up before it hits the Earth. What we do know is that 90% of meteorites that enter the Earth's atmosphere are pretty common, not very interesting, and they do not generate any news at all. Maybe once a day, somebody will find and/or see a basketball size piece that reaches the Earth. In an average month, there will be one the size of a car, found somewhere on Earth. The one that hit Russia was a rare event, a once in a 100 year occurrence. Before this, the last largest meteorite hit on record was known as the 1908 Tunguska Event, when a meteorite hit in Tunguska, Siberia, and what is now Krasnoyarsk Krai, Russia. Although it broke up in the air before it ever hit the Earth, the impact of its blast was about 1,000 times more powerful than the atomic bomb dropped on Hiroshima, Japan. Since then, in 1947, an approximate 70 ton meteorite fell in the Sikhote-Alin Mountains in eastern Siberia. In comparison to the meteor that hit more recently in Indonesia in 2009, this latest one in Russia was four to five times more powerful.
In that these events are similar in impact and magnitude to a nuclear explosion, the international agencies established to monitor nuclear explosions provide the data on them At this point, four agencies in the area have reported an impact. Although they do not know how many at this point, there were several distinct explosions as the asteroid broke up over Chelyabinsk. Scientists do not yet know how far away the blast was felt, more data will come later from the other agencies as well.
This news report is from Russia Today. It is interesting to hear the news from the area and what is actually going on with them. There have been updates since the report was made.
For the information in this article, thanks to:
- NASA Press Services
- Bill Cooke, lead for the Meteoroid Environments Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama.
- Paul Chodas, research scientist in the Near Earth Object Program Office at NASA’s Jet Propulsion Laboratory in Pasadena, California.
- Historic background information courtesy of Wikipedia.com
