Science, Science and Tech

Meteor points to blitz from beyond the stars

Three studies were published last week that had been researching the Chelyabinsk meteor, with scientists concluding that the threat of near-Earth space objects could be 10 times greater than previously thought.

Chelyabinsk_meteor_trace_15-02-2013

The Chelyabinsk meteor exploded in Russia, near the Kazakhstan border on 15 February this year. The meteor entered earth’s atmosphere travelling at a staggering 19km per second and was 19m wide, with the force from the shockwave causing destruction in areas more than 100km away from the impact site. The energy of the meteor was equivalent to an explosion of 500 kilotons of TNT, about the same force as a nuclear bomb. Directly below the fireball’s path, the shockwaves were strong enough to shatter glass windows, injuring 1,500 people and damaging more than 3,500 buildings. At its most intense, the meteor was 30 times brighter than the sun, with the ultraviolet light from the meteor causing sunburn and retinal burns to witnesses.

Between 4,000kg‐and 6,000kg of the meteor fell to Earth, with one of the largest fragments being a 654kg chunk which was recovered from the bottom of Chebarkul Lake on 16 October. Further analysis of the rock led scientists to determine the asteroid was about 4.4 billion years old. Although the results are not infallible, the study published in Nature suggests that the Chelyabinsk meteor originated from a 2km-wide rock, known as asteroid 86039, due to very similar orbit paths.

The event was the biggest impact over land for over a century, with the last incident of this magnitude being the infamous Tunguska event in 1908, which was also in Russia. However, this was the first time that a meteor strike was so well documented, due to the abundance of modern technology. Scientists were able to study the event using typical data sources, such as infrasound and seismic. However, they also used over 400 video clips from the public to further study the asteroid, with footage captured on the ground from residents smart phones and security cameras.

Although asteroids greater than 1km are well known, the Chelyabinsk meteor was much smaller than this and was not detected until after it broke up in the Earth’s atmosphere. This has lead scientists to believe that these events are much more frequent than previously thought, and that we should expect a Chelyabinsk‐sized event at least once every 25 years.

The occurrence of the event has bought much more attention to this area of research, with scientists suggesting that early warning systems need to be implemented. This will allow for the interception and diversion of any threatening space objects, minimising the impacts that could be felt by earth from these sorts of events in the future.

19/11/2013

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