Russian meteor blast heard around the world
When the Chelyabinsk meteor
exploded high over Russia on February 15, it was a blast heard around
the world. This isn't just a figure of speech. Though too low-frequency
for human hearing, sound waves from the 500-kiloton detonation of the
17-meter (56-ft) rock were picked up in Antarctica – some 15,000 km
(9,320 miles) away – by 17 Comprehensive Test Ban Treaty Organisation
(CTBTO) infrasound stations dedicated to detecting nuclear explosions
above or below ground.
The Chelyabinsk meteor was the largest space object to explode on Earth in over a century. It was captured on dramatic videos, knocked down walls, blew in windows and injured about a thousand people as it released as much energy as 30 Hiroshima atomic bombs. It also set off infrasonic waves – sub-audible sounds between 0.001 Hz and 20 Hz. These can travel around the world and are used by the CTBTO’s network of 45 infrasound stations to help enforce treaties against nuclear testing.
The Chelyabinsk meteor was the largest space object to explode on Earth in over a century. It was captured on dramatic videos, knocked down walls, blew in windows and injured about a thousand people as it released as much energy as 30 Hiroshima atomic bombs. It also set off infrasonic waves – sub-audible sounds between 0.001 Hz and 20 Hz. These can travel around the world and are used by the CTBTO’s network of 45 infrasound stations to help enforce treaties against nuclear testing.
“We saw straight away that the event would be huge, in the same order as the Sulawesi event from 2009,” said CTBTO acoustic scientist, Pierrick Mialle. "The observations are some of the largest that CTBTO’s infrasound stations have detected."
The Sulawesi event was the explosion of a bolide meteor over Indonesia, which was recorded by 15 CTBTO stations.
“We know it’s not a fixed explosion because we can see the change in direction as the meteorite moves towards the earth" added Mialle. "It’s not a single explosion, it’s burning, traveling faster than the speed of sound. That’s how we distinguish it from mining blasts or volcanic eruptions. Scientists all around the world will be using the CTBTO’s data in the next months and year to come, to better understand this phenomena and to learn more about the altitude, energy released and how the meteor broke up."
The CTBTO detector stations are located in remote locations in order to minimize natural and man-made background noise. They work by recording minute changes in the atmospheric pressure using microbarometers.
No comments:
Post a Comment