Skip to main content

Planet of sound: Meteor blast resonated around Earth

By Matt Smith, CNN
updated 10:37 AM EST, Thu February 28, 2013
A large chunk of a meteor that exploded over Russia is found in a lake on Friday, February 15. A large chunk of a meteor that exploded over Russia is found in a lake on Friday, February 15.
HIDE CAPTION
Meteor explodes over Russia
Meteor explodes over Russia
Meteor explodes over Russia
Meteor explodes over Russia
Meteor explodes over Russia
Meteor explodes over Russia
Meteor explodes over Russia
Meteor explodes over Russia
<<
<
1
2
3
4
5
6
7
8
>
>>
STORY HIGHLIGHTS
  • Nuclear test sensors picked up meteor's sound wave as far away as Antarctica
  • Scientists used that sound to calculate the size of the space rock
  • Meteor created boom over Russia

(CNN) -- The meteor that exploded over the steppes of southwestern Russia sent a low-frequency rumble bouncing through the Earth, giving scientists new clues about the biggest cosmic intruder in a century.

The big boom over Chelyabinsk on February 15 also produced a wave of sound thousands of times lower than a piano's middle C -- far below the range of human hearing, according to the international agency that watches for nuclear bomb tests. The Comprehensive Test Ban Treaty Organization said that sound wave showed up on sensors from Greenland to Antarctica, making it the largest ever detected by its network.

Scientists then used that wave to calculate the size of the small asteroid that plunged to Earth, said Margaret Campbell-Brown, an astronomer at Canada's University of Western Ontario.

The duration of the wave -- about 32 seconds -- let scientists estimate the energy of the blast at between 450 and 500 kilotons, the size of about 30 early nuclear bombs

Meteor streaks through Russian skies
Russian meteor was like 'a rocket bomb'
Over 100 tons of material falls daily

From there, Brown said, they could calculate the size of the fireball; and using an estimate of the meteor's speed from the numerous dashboard and mobile-phone cameras that captured the scene, it was "first-year physics" to figure out the approximate size and weight, she said.

The latest estimate is that the Chelyabinsk meteor was about 56 feet (17 meters) across, weighed more than 7,000 tons and was moving about 18 kilometers per second (40,000 mph) when it blew apart, she said.

Opinion: A meteor and asteroid: 1 in 100 million odds

"In terms of things we have observed, this is the largest since Tunguska," Brown said, referring to the suspected meteor that flattened a Siberian forest in 1908.

The nuclear test monitors pick up "infrasound", or low frequency, waves from about 20 meteors a year -- "if conditions are right, perhaps as small as a pea," she said.

Russian authorities say more than 1,500 people were hurt, mostly by flying glass, when the Chelyabinsk meteor exploded in spectacular fashion. Amateur video footage showed a bright white streak moving rapidly across the sky before exploding with an even brighter flash and a deafening bang.

Bill Cooke, head of NASA's Meteoroid Environment Office, said scientists believe the object originated in the asteroid belt between Mars and Jupiter. It was the Apollo group of asteroids, which circle the sun in oblong orbits, that occasionally cross Earth's.

Cooke said scientists expect to study the Chelyabinsk event for months. But the dozens of fragments that have been found so far point to a fairly common, stony asteroid with traces of nickel and iron.

"The composition is not at all unusual as far as meteorites go," he said. "It was just very big."

More space and science news on CNN's Light Years blog

ADVERTISEMENT
Part of complete coverage on
updated 10:27 AM EDT, Wed July 23, 2014
Hamas' tactics have changed -- now the group is using commando-like tactics, says CNN's Ben Wedeman.
updated 11:40 AM EDT, Sun July 20, 2014
Some contend that larger weapons have come into Ukraine from Russia.
updated 5:51 PM EDT, Tue July 22, 2014
A nun, an AIDS researcher, an athlete and a family traveling on summer vacation. These were some of the victims aboard MH17.
updated 8:21 PM EDT, Mon July 21, 2014
Prince George isn't your average one year old. He started walking before he was one. Oh, and, he's going to be king -- of 16 countries.
updated 7:36 AM EDT, Mon July 21, 2014
Former President Bill Clinton acknowledges he got "very close" to helping achieve peace in the Middle East.
updated 2:21 AM EDT, Fri July 18, 2014
In an ambitious plan to upgrade urban India, Prime Minister Narendra Modi says he will build 100 "smart cities" across the country.
updated 7:27 AM EDT, Sun July 20, 2014
Inspirational, creepy or just weird? CNN meets the 51-year-old man who dresses like a schoolgirl.
updated 7:00 AM EDT, Thu July 17, 2014
A British nanotech company has created what it says is the world's darkest material.
updated 7:12 AM EDT, Fri July 18, 2014
Yoga, meditation and watching a snake eat a frog alive: these are some of the experiences to be had at this Himalayan yoga retreat.
updated 7:52 AM EDT, Tue July 22, 2014
The world's largest flying aquatic insect, with huge, nightmarish pincers, has been discovered in China's Sichuan province, experts say.
CNN joins the fight to end modern-day slavery by shining a spotlight on its horrors and highlighting success stories.
Browse through images from CNN teams around the world that you don't always see on news reports.
ADVERTISEMENT