Asteroid threat greater than experts thought
WASHINGTON — Scientists studying the terrifying meteor that exploded without warning over a Russian city last winter say the threat of space rocks smashing into Earth is bigger than they thought.
Meteors about the size of the one that streaked through the sky at 42,000 mph and burst over Chelyabinsk in February — and ones even larger and more dangerous — are probably four, five or even seven times more likely to hit the planet than scientists believed before the fireball, according to three studies published Wednesday in the journals Nature and Science.
That means about 20 million space rocks the size of the Chelyabinsk one may be zipping around the solar system, instead of 3 million, NASA scientist Paul Chodas said at a news conference.
Until Chelyabinsk, NASA had looked only for space rocks about 100 feet wide and bigger, figuring there was little danger below that.
This meteor was only 62 feet across but burst with the force of 40 Hiroshima-type atom bombs, scientists say. Its shock wave shattered thousands of windows, and its flash temporarily blinded 70 people and caused dozens of skin-peeling sunburns just after dawn in icy Russia. More than 1,600 people in all were injured.
Up until then, scientists had figured a meteor causing an airburst like that was a once-in-150-years event, based on how many space rocks have been identified in orbit. But one of the studies now says it is likely to happen once every 30 years or so, based on how often these things are actually hitting.
By readjusting how often these rocks strike and how damaging even small ones can be, “those two things together can increase the risk by an order of magnitude,” said Mark Boslough, a Sandia National Lab physicist, co-author of one of the studies.
Lindley Johnson, manager of NASA's Near Earth Object program, which scans the heavens for dangerous objects, said the space agency is reassessing what size rocks to look for and how often they are likely to hit. It also looking into how the government should react if an asteroid is headed for Earth.
In addition, NASA this fall reactivated a dormant orbiting telescope called WISE specifically to hunt for asteroids, Johnson said. The agency is expanding ground-based sky searches that might give a few extra days' notice of smaller meteors like the Russian one.
Show commenting policy
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.
- Nurse defies Maine quarantine in standoff over Ebola
- Few knew of cyber attack on White House computer network
- Unaccompanied immigrants put heavy strain on schools, charities
- Museum saves part of bomber plant
- Hawaii’s National Guard sent to lava flow site
- Terminally ill woman may delay planned Nov. 1 suicide
- Gray wolf sighting reported at Grand Canyon
- Botched probe of suspected arms dealer echoed Fast and Furious, watchdog finds
- Plane slams into pilot training center at Kansas airport, killing 4
- Ferguson grand jury cleared in leaks about police shooting of black teenager
- Hillary Clinton’s remark at Mass. rally about jobs left out words, aide says