On February 15th, the Chelyabinsk meteor streaked through the Siberian sky, unleashing a sonic blast that reached across the globe.
In numerous videos of the event, an audible sonic boom could be heard after the meteor entered the Earth’s atmosphere – but the audible sound was just the tip of the iceberg. The meteor also released a wave of infrasound – a sound wave in the range of 0.001 to 20 Hz, far below what humans can hear. This infrasound wave could be heard as far off as Antarctica!
So how do we know about it in the first place?
The Comprehensive Test Ban Treaty Organization (CTBTO) monitors the Earth for nuclear weapon detonations. Spotting city-sized explosions is surprisingly hard, and to do so, the CTBTO uses a series of infrasound listening stations across the globe.
When the Chelyabinsk meteor entered the atmosphere, CTBTO scientists were some of the first to hear it. According to Pierrick Mialle, a CTBTO acoustic scientist, “The observations are some of the largest that CTBTO’s infrasound stations have detected." In fact, the Chelyabinsk event was detected by forty-five different CTBTO stations, three times as many as heard the Sulawesi meteor explosion in 2008.
One could justifiably ask the CTBTO how, exactly, they knew the loud explosion in Russia was a meteor and not the start of World War III. “We know it’s not a fixed explosion because we can see the change in direction as the meteorite moves towards the earth,” explains Maille, “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
The CTBTO’s data will be analyzed by scientists around the world in the coming months. With further study, we’ll be able to put together a better picture of the energy the meteor released, and its configuration when it exploded, using a sound that no one ever heard.eruptions.”
Watch and Listen to the Infrasound Blast Recorded by the CTBTO’s Sensors Below:
Images and Video Courtesy of CTBTO and