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
This looks like a ghost ship, but it's actually the site of a tense international standoff between the Philippines and China.
updated 11:55 AM EDT, Sat July 26, 2014
The reported firing of artillery from Russian territory is a sign Vladimir Putin has escalated the Ukraine battle, says CNN's military analyst Rick Francona.
updated 4:46 AM EDT, Sun July 27, 2014
The young boy stops, stares, throws ammunition casings at the reporter's feet without a word.
updated 8:37 AM EDT, Sun July 27, 2014
A picture taken on June 28, 2014 shows a member of Doctors Without Borders (MSF) putting on protective gear at the isolation ward of the Donka Hospital in Conakry, where people infected with the Ebola virus are being treated. The World Health Organization has warned that Ebola could spread beyond hard-hit Guinea, Liberia and Sierra Leone to neighbouring nations, but insisted that travel bans were not the answer.
The worst ebola outbreak in history spreads out of control in West Africa. CNN's Michael Holmes reports.
updated 8:48 PM EDT, Fri July 25, 2014
Sure, Fido is a brown Lab. But inside, he may also be a little green.
updated 4:06 PM EDT, Thu July 24, 2014
ITN's Dan Rivers reports from the hospital where those injured by an attack in Gaza were being treated.
updated 9:03 AM EDT, Mon July 28, 2014
Photograph of an undisclosed location by Patrycja Makowska
Patrycja Makowska likes to give enigmatic names to the extraordinarily beautiful photographs she shoots of crumbling palaces.
updated 4:04 AM EDT, Wed July 23, 2014
When the Costa Concordia and its salvage convoy finally depart Giglio, the residents will breathe a sigh of relief -- and shed a tear.
updated 2:08 PM EDT, Fri July 25, 2014
Flight attendants are wearing black ribbons to show solidarity with fallen colleagues in "a tribute to those who never made it home."
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