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 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 12:47 AM 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."
updated 9:24 AM EDT, Fri July 25, 2014
Hamas: "Lift the siege." Israel: "End the rockets." The two sides' demands will be difficult to reconcile.
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 4:53 PM EDT, Tue July 22, 2014
CNN's Richard Quest speaks to Malaysia Airlines' Hugh Dunleavy about how the airline industry needs to react to MH17.
updated 4:42 PM EDT, Thu July 24, 2014
From Maastricht to Melbourne, and baroque theaters to block-long warehouses, these stores make bookish travelers look stylish.
updated 2:57 PM EDT, Wed July 23, 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 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.
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.
updated 9:17 AM EDT, Fri July 25, 2014
After just one day of competition, a new sport has emerged at the Commonwealth Games in Glasgow: snapping selfies with the Queen.
ADVERTISEMENT