Asteroid Warnings Toned Down

Astronomers have significantly softened the wording of the Torino scale -- an asteroid risk-assessment system for evaluating the danger of Earth-bound meteors.

Akin to the Richter scale, the Torino scale goes from zero to 10, with zero representing no risk and 10 warning of an impact that could wipe everything off the planet. But scary phrases from the old warning system like "localized destruction," "regional devastation" and "certain global climatic catastrophe" have been modified.

Scientists hope the rewording will better explain to the public what these phrases mean without causing concern.

"This has been an ongoing effort to try to come up with reasonable ways to communicate discoveries when we find an object that's going to pass close to the Earth," said Richard Binzel, professor of planetary science at MIT, who drafted the new Torino wording.

The outdated wording, agreed upon in 1999 in Torino, Italy, by the International Astronomers Union, used alarming language sometimes resulting in doomsday headlines like the Kansas City Star's "Look! Up in the sky! A big asteroid is heading our way!!" (registration required).

Although astronomers are happy to make their findings public, they don't want to scare the public unnecessarily, said Donald Yeomans, manager of NASA's Near Earth Object Program Office.

"It certainly isn't meant to be frightening," he said.

Many of the potentially threatening objects tracked by astronomers have independent orbits that may cause them to collide with Earth at some point. Some objects, like Halley's Comet, swoop through the neighborhood only once a century or so.

In the old wording, a level 4 asteroid was described as an object with "a 1 percent or greater chance of collision capable of causing regional devastation." The new version explains that the object merits only the concern of astronomers and continued observation would probably reassign the comet to a level zero -- in other words, the asteroid likely will whiz by.

Although there is still a 1 percent chance of a level 4 asteroid hitting Earth, the general public is now told not to worry when NASA's Near Earth Object Program Office issues a warning.

"It's a good thing that astronomers keep track of these low-scale events, but there is no need for public concern," said Binzel.

Like the Department of Homeland Security's terror alert system, the Torino scale uses five different colors that correspond to the severity of a potential impact. The colors haven't changed from the old system, but the explanation of what each color means has. Asteroids in the green section used to be deemed "events meriting careful monitoring," but now are considered "normal." And a level 6 object was described as capable of causing "global catastrophe." Now these, too, only merit the concern of astronomers.

Governments are specifically advised not to prepare for a disaster from a level 6 warning unless the collision is within the decade.

Not all the changes paint a rosier picture. Under the old system, a level 10 warning used to be described as "causing global climatic disaster." The new description reads "a certain collision capable of causing global climatic catastrophe that may threaten the future of civilization as we know it."

But the changes in wording will have little effect on astronomers. That's because the calculations used to determine how threatening a comet is will remain exactly the same.

Astronomers often need time before they can know for sure where an asteroid is headed and the risk it poses.

"When we discover an object, the most likely outcome is that when we have enough data the object will go away," said Binzel. "The previous system didn't communicate that."

Critics have blamed the Torino scale's alarming scientific talk for causing media frenzies.

"It was written by scientists and reviewed by scientists but I can see that for folks not familiar with this topic it might have looked a little frightening," said Yeomans.

To date, the highest level a comet has been rated is 4. In December 2004, an asteroid had a 1 in 45 chance of hitting Earth by 2029. Newly analyzed data caused that warning to wane.

Scientists suspect there are 1,100 celestial objects large enough to cause a doomsday impact. NASA's Near Earth Object Program Office says 765 come close to crossing Earth's orbit.

Neither Binzel nor Yeomans believe we are presently at risk.

With images from movies like Armageddon and Deep Impact fueling the public's fears, astronomers hope the new Torino wording will do a better job of explaining data about asteroids and quell overreaction to initial findings.

"It's not even a warning system," said Binzel. "It's better thought of as an information system."

< Interesting phenomenon here. Is this unnecessary censorship because the original plan said what it meant and meant what it said? Or is the concession to usability, as in people can't deal with the simple truth, the proper thing to do? Only time will tell... >