A hunk of space debris hurtling toward Earth at 17,000 mph is expected to come startlingly close in 2028, astronomers said Wednesday.
Whether the mile-wide asteroid will actually collide with Earth is still open to question.
The chances of it hitting our planet at this point are zero, according to senior researcher Don Yeomans at the Jet Propulsion Laboratory in Pasadena. But other asteroid specialists are raising the specter of Armageddon.
"It scares me," astronomer Jack G. Hills of Los Alamos National Laboratory said. "An object this big hitting the Earth has the potential of killing many, many people."
Yeomans conceded that he had not yet seen the latest data on the asteroid's orbit. Using data from December, when the object was discovered by astronomers at the University of Arizona Spacewatch Program, through February, he calculated "a formal impact probability of zero."
Ben Weiss, an astronomer at Caltech, said he and his colleagues there had not yet heard of the object, but added that he trusted Yeomans' assessment. "Don Yeomans is one of the world's experts," he said.
Although it is highly unusual for an object of such size to pass so close to Earth, Yeomans said, "it's nothing to lose sleep over." Still, he said, he'd like to have the data from March.
Astronomer Brian Marsden of the International Astronomical Union, which circulated the news about the object, said it is nothing to worry about, even if it were on a collision course with Earth. In 30 years, technology should be available to deflect it, he said.
"What would be scary is if it were three days from now or three weeks or even three years," Marsden said. "Thirty years is just right because it's far enough in the future."
Still, Hills raised the prospect of widespread global destruction. "If one like this hit in the Atlantic Ocean," Hills said, "where cities stood would only be mud flats."
Astronomer Steven Maran of the American Astronomical Society agreed: "It has enormous destructive potential."
Earlier this month, astronomers at the University of Texas calculated that the asteroid would come within 30,000 miles of Earth on Oct. 26, 2028, at 1:30 p.m. Eastern Daylight Time. Although the estimate has an error range of 180,000 miles, that number is misleading, Yeomans said, and still doesn't mean the asteroid has a probability of hitting Earth.
From a research perspective, however, the object is very exciting, Yeomans and Marsden said. Known as asteroid XF11, the object is one-tenth to one-fifth the size of the asteroid that is thought to have collided with Earth and led to the extinction of the dinosaurs--and most other species inhabiting the planet--65 million years ago.
And even if it passes by Earth at a distance of 200,000 miles, it would still be within the Moon's orbit, Marsden said. "If it really is as close as 30,000 miles it will really be quite bright," he said. "It will be evening in Europe and will be visible there with the naked eye. It would actually be a rather nice thing to see."
Yeomans agreed: "It's an outstanding scientific opportunity. Scientists will be training every imaginable telescopic instrument on it. But I don't think it's a worry."
Still, he added, from a Hollywood standpoint, the asteroid announcement is very well-timed. Bruce Willis stars in a major film about an asteroid hitting the Earth, and "Armageddon" is due out soon. "Willis should be ecstatic," he said.
Times wire services contributed to this story.