November 6, 2013

Studies warn about space rock threat

The meteorite that hit over Russia indicates collisions are up to five times as likely as originally thought.

By Seth Borenstein
The Associated Press

(Continued from page 1)

click image to enlarge

In this screen image made from a dashboard camera video shows a meteor streaking through the sky over Chelyabinsk, about 930 miles east of Moscow on Feb. 15, 2013. The meteor hit Earth at 42,000 mph and exploded over the Russian city, smashing windows and causing minor injuries.

The Associated Press

click image to enlarge

This photo provided by The Field Museum in Chicago shows pieces of the meteor that exploded over Russia’s Ural Mountains in February after they were catalogued on their arrival at the museum. The museum received nearly two pounds of small meteorite pieces donated by a collector.

The Associated Press

After the government drill, NASA and Federal Emergency Management Agency officials said they should look at the need for evacuations, figure out better ways of keeping the public informed without scaring them, and handle meteor threats in a way comparable to how they deal with hurricanes bearing down on the coast.

NASA also got a wake-up call this week on those bigger space rocks that astronomers thought they had a handle on, discovering two 12-mile-wide space rocks and a 1.2-mile-wide one that had escaped their notice until this month.

The three objects won’t hit Earth, but their discovery raises the question of why they weren’t seen until now.

The last time a 12-mile-wide rock had been discovered was about 30 years ago, and two popped into scientists’ view just now, NASA asteroid scientist Donald Yeomans said. He said NASA had thought it had already seen 95 percent of the large space rocks that come near Earth.

Asteroids are space rocks that circle the sun as leftovers of failed attempts to form planets billions of years ago. When asteroids enter Earth’s atmosphere, they become meteors. (When they hit the ground, they are called meteorites.)

The studies said the Chelyabinsk meteor probably split off from a much bigger space rock.

What happened in Russia is altering how astronomers look at a space rocks. With first-of-its-kind video, photos, satellite imagery and the broken-up rock, scientists have been able to piece together the best picture yet of what happens when an asteroid careens into Earth’s atmosphere. It’s not pretty.

“I certainly never expected to see something of this scale or this magnitude,” said University of Western Ontario physicist Peter Brown, lead author of one study. “It’s certainly scary.”

Scientists said the unusually shallow entry of the space rock spread out its powerful explosion, limiting its worst damage but making a wider area feel the effects. When it burst it released 500 kilotons of energy, scientists calculated.

“We were lucky. This could have easily gone the other way. It was really dangerous,” said NASA meteor astronomer Peter Jenniskens, co-author of one of the papers. “This was clearly extraordinary. Just stunning.”

Were you interviewed for this story? If so, please fill out our accuracy form

Send question/comment to the editors




Further Discussion

Here at PressHerald.com we value our readers and are committed to growing our community by encouraging you to add to the discussion. To ensure conscientious dialogue we have implemented a strict no-bullying policy. To participate, you must follow our Terms of Use.

Questions about the article? Add them below and we’ll try to answer them or do a follow-up post as soon as we can. Technical problems? Email them to us with an exact description of the problem. Make sure to include:
  • Type of computer or mobile device your are using
  • Exact operating system and browser you are viewing the site on (TIP: You can easily determine your operating system here.)