A team of Colombian astronomers have painstakingly reconstructed the path of the meteor that captured the world’s attention earlier this month after smashing into the Russian countryside, leaving hundreds of people injured.
The results of the study, announced Wednesday, reveal the 45-foot-wide meteor was destined to smash into Earth. Using evidence gathered by one camera at the Revolution Square in the city of Chelyabinsk and other videos recorded by witnesses in the close city of Korkino, the team was able to calculate the trajectory of the body in the atmosphere, which allowed them to reconstruct its orbit around the sun.
Relying on the collection of footage, the team was able to use the Naval Observatory Vector Astrometry Software (NOVAS) in order to determine the location, speed, and altitude of the fireball as it slammed into Earth’s atmosphere. The software system was able to add in various factors of influence, including the gravitational tug from the moon and that of the other eight planets. The resulting equation allowed the astronomers to posit that the Russian meteor was once an Apollo-class asteroid. Apollo-class asteroids are part of a well known collection of near-Earth objects that often result in close flybys of Earth. According to NASA, 5,200 Apollo-class asteroids are currently known, the largest being 1866 Sisyphus — a 10 kilometer-wide monster that was discovered in 1972.
The first firm details of the 15 February asteroid impact in Russia, the largest in more than a century, are becoming clear. ESA is carefully assessing the information as crucial input for developing the Agency’s asteroid-hunting effort.
At 03:20 GMT on 15 February, a natural object entered the atmosphere and disintegrated in the skies over Chelyabinsk, Russia.
Extensive video records indicate a northeast to southwest path at a shallow angle of 20° above the horizontal. The entry speed is estimated at around 18 km/s - more than 64 000 km/h.
According to calculations by Peter Brown at the University of Western Ontario, Canada, drawing on extremely low-frequency sound waves detected by a global network, the object is estimated to have been about 17 m across with a mass of 7000-10 000 tonnes when it hit atmosphere.
It exploded with a force of nearly 500 kilotons of TNT - some 30 times the energy released by the Hiroshima atomic bomb - around 15-20 km above the ground.
With our current understanding of near-Earth objects, events of this magnitude are expected once every several of tens to 100 years.
Using sensors designed to detect rogue nuclear tests, scientists have learned more about the meteor that exploded over Russia. It was much bigger than they first thought.
The meteor that exploded over the Ural Mountains in Russia Friday now appears to have been a small asteroid clearly unrelated to 2012 DA14, which flitted past Earth Friday afternoon.
Initially, the Russian Academy of Science estimated the object’s mass at about 10 metric tons (11 US tons). With more data in hand, researchers now say the object had a mass of 7,000 metric tons (7,700 US tons) and a diameter of about 50 feet.
The blast released energy comparable to a 300- to 500-kiloton nuclear warhead, says Bill Cooke, who heads the meteoroid environment office at NASA’s Marshall Space Flight Center in Hunstville, Ala. By Comparison, the Nagasaki nuclear bomb had a yield of 20 to 22 kilotons.
The asteroid’s breakup at an altitude some 12 to 15 miles above Russia’s Chelyabinsk region represents the largest recorded asteroid encounter since 1908, when another asteroid or comet exploded over the Tunguska River in Siberia, leveling some 820 square miles of forest, says Paul Chodas, a scientist with the near-Earth object program at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.
The shock waves from what appear to have been multiple blasts, perhaps triggered as large initial fragments underwent their own disruption, broke windows in the three major cities in the region, including Chelyabinsk. At least 950 people were injured, although most of the injuries were minor, according to reports from the area.
“What an amazing day for near-Earth objects. By an incredible coincidence we have two rare events happening on the very same day,” Dr. Chodas said during a briefing Friday afternoon.