Skip to main content

Tough to spot: Chelyabinsk meteor tinted by ancient crashes

By Matt Smith, CNN
October 10, 2013 -- Updated 1318 GMT (2118 HKT)
(File) The trail of a falling object is seen above a residential apartment block in the Urals city of Chelyabinsk.
(File) The trail of a falling object is seen above a residential apartment block in the Urals city of Chelyabinsk.
STORY HIGHLIGHTS
  • The space rock that blew up over Russia had been darkened by ancient crashes
  • "Dark asteroids are harder to detect because they reflect less light," scientist says
  • The meteor injured about 1,500 people when it crashed to Earth in February
  • Scientists have found about 100 pieces, the biggest of which is about 11 pounds

(CNN) -- The meteor that blew up over southwestern Russia in February had survived long-ago collisions that blackened its surface, making it harder to spot, a scientist who studied its pieces said Wednesday.

The roughly 60-foot space rock plunged into Earth's atmosphere and exploded over the Russian city of Chelyabinsk with the force of about 30 early nuclear bombs. Of the roughly 100 fragments found so far, the biggest weighs about 11 pounds (5 kilograms), said Maria Gritsevich, a researcher at the University of Helsinki.

Read more: Saving Earth from asteroids

Gritsevich and others who have studied those fragments have found the small asteroid was mostly made of ordinary rock.

Watch this streaking asteroid
Perseid meteor shower lights up the sky
Russian meteor was like 'a rocket bomb'

But it was marbled with metallic elements such as iron -- and when the asteroid collided with other bodies floating around the solar system, the heat and force of that impact melted the metal, which seeped into fissures in the surface of the stone and blackened its surface.

"Dark asteroids are harder to detect because they reflect less light," Gritsevich, who presented her findings at an American Astronomical Society conference this week, told CNN.

Planet of sound: Meteor blast resonated around Earth

While most ordinary rocky asteroids reflect up to 20% of the sunlight that strikes them, and Earth reflects about 40%, dark asteroids reflect 5% of the light or less, she said.

The meteorites collected from the Chelyabinsk incident show varying signs of darkening, with some completely blackened, others made up entirely of light-colored stone and some with a mixture of coloration, Gritsevich said.

"All Chelyabinsk meteorites look different," she said. "You can clearly distinguish three different groups."

She said scientists are still working to determine the age of the Chelyabinsk meteor, the largest to hit Earth since the 1908 Tunguska incident in Siberia.

NASA estimates 4,700 'potentially hazardous' asteroids

The blast left more than 1,500 injured, mostly by glass from shattered windows, and raised concerns about humanity's vulnerability to stray asteroids.

Two months later, NASA announced a goal of sending a spacecraft out to seize and asteroid and tow it into orbit around the moon, where it could be studied by astronauts -- a project billed in part as a planetary defense mission. But it ran into opposition in Congress, where a House committee voted to block any funding for the mission in July.

ADVERTISEMENT
Part of complete coverage on
December 16, 2014 -- Updated 2245 GMT (0645 HKT)
Pakistan Taliban say the school attack was revenge for the killing of children in a military offensive -- but they are being pressed by defections to ISIS.
A group that claims it hacked Sony Pictures has posted a public threat against moviegoers who see Sony's "The Interview."
December 18, 2014 -- Updated 0243 GMT (1043 HKT)
The gunman behind the deadly siege in Sydney this week was not on a security watch list, and Australia's Prime Minister wants to know why.
December 18, 2014 -- Updated 0948 GMT (1748 HKT)
Bestselling author Marjorie Liu had set her sights on being a lawyer, but realized it wasn't what she wanted to do for the rest of her life.
December 16, 2014 -- Updated 2027 GMT (0427 HKT)
CNN's Matthew Chance looks into an HRW report saying Russia has "legalized discrimination against LGBT people."
December 16, 2014 -- Updated 0212 GMT (1012 HKT)
The Sydney siege has brought home some troubling truths to Australians. They are not immune to what are often called "lone-wolf" terror attacks.
December 16, 2014 -- Updated 0012 GMT (0812 HKT)
A social media campaign condemning Islamophobia under the hashtag #illridewithyou has taken off after Sydney hostage siege.
Bill Cosby has kept quiet as sexual assault allegations mounted against him, but his wife, Camille, finally spoke out in defense of her husband.
December 15, 2014 -- Updated 1144 GMT (1944 HKT)
China-bound AirAsia flight turns back to Bangkok after passenger throws water over crew member.
December 15, 2014 -- Updated 1026 GMT (1826 HKT)
It takes Nepalese eye doctor, Sanduk Ruit about five minutes to change someone's life.
December 16, 2014 -- Updated 1054 GMT (1854 HKT)
This epic journey crosses 13,000 kilometers, eight countries over 21 days. Find out where.
December 19, 2014 -- Updated 1431 GMT (2231 HKT)
Each day, CNN brings you an image capturing a moment to remember, defining the present in our changing world.
Browse through images from CNN teams around the world that you don't always see on news reports.
ADVERTISEMENT