Deadly Space Rubble Asteroids Pose A Threat To Earth But Movie Portrayals Can Stray From Reality, Scientists Say

Killer asteroids are edging out volcanos as the entertainment industry’s disaster of choice. No fewer than three high-profile programs are devoted to the space rocks on television this month.

The asteroid shower begins this weekend, when viewers can catch “Three Minutes to Impact,” a two-hour documentary at 4 p.m. today on The Discovery Channel, then watch the opening installment of the four-hour NBC miniseries “Asteroid” at 9.

Later this month, NBC presents the National Geographic special “Asteroids: Deadly Impact” (Feb. 26), which traces the work of geologist Eugene Shoemaker, the meteorite expert credited with convincing the scientific world that asteroid impacts have played a big role in Earth’s geological history.

Judging from the titles, the specter of doom is a big selling point for asteroid programs. But how realistic is the danger, and how accurate is NBC’s fictional account of a 4-mile-wide asteroid traveling at 34,000 miles an hour with the Earth in its sights?

Brian Marsden, associate director for planetary sciences at the Harvard-Smithsonian Center for Astro-Physics in Cambridge, Mass., hasn’t seen the miniseries. But he’s dubious about whether it’s factually sound. For instance, “Asteroid’s” explanation for the rock’s course toward Earth involves a collision with a comet, which knocks it out of the asteroid belt between Mars and Jupiter.

“Utterly crazy,” Marsden said. “It’s more likely that a 1-mile-(wide) asteroid would come at us tomorrow because its orbit intersects with Earth’s than for a comet to collide with an asteroid and send it toward the Earth.”

The odds against two objects colliding in space, then propelling fragments at the Earth are high enough to make such a scenario virtually impossible, he said.

The 4-mile-wide asteroid in the miniseries is named Eros, which happens to be the name of a real asteroid discovered in 1898. But the real asteroid is more than twice as large and conceivably could hit Earth in a million years at the earliest, Marsden said.

“There’s a community of astronomers that work with near-Earth asteroids,” he said. “As far as we can ascertain, none of us were consulted.”

NBC says scientific theory is less important than creating a dramatic story line.

It’s entertainment, says “Asteroid” supervising producer Peter Ware. He says the miniseries was created with input from the Defense Department, astronomers and artists at the Griffith Observatory in Los Angeles, but viewers who want a documentary should catch “Nova.”

“When you talk to these guys, you have to glean the information that tells your story,” Ware said. “We’re not doing the scientific rendition of an asteroid hit. Obviously we have to take some creative license.”

Is NBC’s portrayal of an asteroid’s globally destructive power on the mark? What Marsden, a world-renowned expert, says about the realistic potential for a devastating strike isn’t reassuring.

“There is previous evidence of things like that,” he said. “You never know when one could come and make other species extinct so the next intelligent life is based on cockroaches or something like that. Our surveillance is so bad that something could sneak up on us.”

Asteroids and comets are the remnants of unformed planets - rubble left over from the creation of the solar system.

It’s estimated there are at least 100 million objects the size of a house moving throughout space. An asteroid must be the size of a four-story building before it’s considered really dangerous, Marsden said.

Research by ecological historians indicates that major impacts have occurred on Earth every 26 million to 30 million years. A killer asteroid is linked to the extinction of the dinosaurs 65 million years ago. But smaller objects can do damage, too.

“They like cars,” Marsden said, only half joking.

In 1992 Michelle Knapp thought she heard a car accident outside her house in Peekskill, N.Y. When she went outside, she saw that a 4-billion-year-old chunk of stone and iron the size of a football had crumpled the trunk of her 1982 Malibu, significantly increasing its value.

She sold the car for $69,000 - nice, compared to the $1,000 she paid for it.

Not everyone could be that lucky, and it’s unlikely a person would be killed by an asteroid strike; odds are about the same as dying in an airplane crash. But the statistical probabilities of predicting a single event are extremely unreliable, Marsden said.

“When you’ve only got one event, odds are a dangerous thing to talk about,” he said. “It might be 100,000 years away, or it might be tomorrow.”

Indeed, with timing that would make an NBC publicist smile, scientists in January spotted an Aten asteroid - one in a group of 24 such objects that frequently cross Earth’s orbit.

As wide as three football fields, the asteroid crossed the Earth’s orbit several times, missing the planet by 10 million miles - a close call in astronomical terms. The asteroid will continue to slice through the Earth’s orbit every 9-1/2 months or so as it travels around the sun.

Eleanor Helin, a scientist at the Jet Propulsion Laboratory in Pasadena, Calif., is tracking the Aten asteroid. Like Marsden, she predicts a major asteroid could slam into the Earth.

“Certainly in time it will happen, as it happened in the past,” she said. “These objects present an almost continuous threat to the Earth because they have very small orbits. They have an ultimate fate of probably colliding with the Earth.”

Helin hasn’t seen the NBC miniseries, but she takes issue with one plot twist, in which officials launch airborne lasers from F-16 fighter jets to blast apart the 4-mile-wide asteroid.

“No way, with an object of a kilometer or even half that size, is that going to be effective,” Helin said. “That’s laughable.”

Scientists say lasers are an option to protect against asteroids but not a mere 23 hours from impact - as in the miniseries.

What is needed, they say, is more money for research that could provide warnings of potential threats up to 10 years in advance. The federal government now spends less than $1 million a year to fund Near-Earth Asteroid Tracking (NEAT), an asteroid surveillance program.

Scientists observe 3 percent of the solar system’s near-Earth objects, a figure that could be 30 times higher with an annual budget of $10 million, Marsden said.

“Instead of putting all this money into movies where we’re wringing our hands and talking about it, all that money could be put into research so we wouldn’t have to worry about it,” he said.

MEMO: This sidebar appeared with the story: Facts from out of this world In NBC’s “Asteroid,” the highest-profile TV program about space rocks this month, a comet passing through an asteroid belt dislodges several large asteroids and sends them heading toward Earth. Astronomers question the plausibility of that plot. Here’s what scientists know about such near-Earth objects: Asteroids, meteorites, comets: How are they different? Comets and asteroids are pieces of planets that never formed, essentially rubble left over from the creation of the solar system. Asteroids, made of rock, are mostly found in the Asteroid Belt between Jupiter and Mars. Asteroids can enter Earth’s atmosphere, where they generally disintegrate before hitting the ground. Odds against a huge asteroid falling to Earth are extremely high, but smaller objects - the size of a football - reach the ground more often. Comets, composed of ice rather than solid rock, exist in the outer reaches of the solar system. Though comets and asteroids could collide, the chances of such a collision sending an object toward Earth is remote, scientists say. Meteorites are tiny bits of asteroids that occasionally fall to Earth. They enter the Earth’s atmosphere at about 11.2 kilometers per second - or 40 times the speed of sound. How many big space rocks are out there? There are at least 100 million objects moving about in the solar system that are the size of a house. Objects as wide as 4 miles, the size of NBC’s fictional asteroid, are being tracked. How often do these space rocks fall to Earth? Major impacts with Earth occur perhaps once every 300,000 years, as best scientists can tell. Documented incidents include the explosion of a 150-foot diameter meteor in 1908 in the air above Siberia, which leveled about 1,000 square miles of wilderness. In 1994 the Shoemaker-Levy comet struck Jupiter with an impact 500,000 times the Siberia hit. Jim Abbott The Orlando Sentinel