27 August 2004

Amateur astronomers help NASA find killer asteroids

Neil Samson Katz, Columbia News Service

On a cloudy afternoon last January, the Air Force's powerful, computerized telescopes in New Mexico picked up a 30-meter (100-feet) wide asteroid. At first it seemed like thousands of others orbiting the solar system, but quick analysis showed it was potentially on a collision course with the Earth, and that this calamity might be only 36 hours away. Scientists calculated the collision had a 40 percent chance of happening, most likely in the form of an explosion in the upper atmosphere with the force of a one-megaton bomb.

As scientists for NASA worked to keep track of the asteroid's position, heavy clouds moved over the primary telescopes in America and Europe, rendering them blind. They spent nine hours trying to spot it, but failed to get a clear picture of where the asteroid was headed. Finally, its location was pinpointed not by NASA's elite but by an amateur astronomer named Brian Warner.

Warner, 42, a computer programmer, was closing his backyard telescope down for the night when he received an e-mail from a senior scientist at the Space Science Institute in Boulder, Colorado, asking him to look at the patch of sky where asteroid 2004 AS1 would be if it was going to hit the Earth. To everyone's relief, it wasn't there. It eventually flew by the planet from the comforting distance of 8 million miles.

The fact that NASA called on Warner in a pinch says much of the vital role that amateur astronomers are playing in helping the agency track potentially dangerous asteroids flying around our neighborhood.

Despite an annual budget of over $6 billion and the astonishing human talent that lets NASA land robots on Mars and telescopically view the farthest reaches of space, the agency has not devoted the resources to tracking the thousands of asteroids in our vicinity, some of which may one day hit the Earth. Instead, they have come to rely on a cadre of backyard stargazers armed with powerful telescopes, sophisticated computer software and a new generation of digital cameras.

"I don't think we could do it without their contributions," said David Morrison, one of the founders of Spaceguard, the NASA program assigned to track near-Earth asteroids.

While most asteroids are first discovered by automated telescopes at NASA, the Air Force or university observatories, it's the amateurs who do the arduous work of tracking them over time. This is critical to determining where they are headed.

Every night the bodies spied by major observatories are published on the Web site of the Minor Planet Center, a clearinghouse for asteroid discoveries. From there, amateurs choose asteroids to observe, noting their position, shape, composition and orbit. This activity not only provides a mapping service for science but also keeps track of asteroids on a collision course with Earth.

While it is highly unlikely that a killer asteroid is headed this way any time soon, the eventual threat is very real. The Spaceguard program is tracking 2,700 near-Earth asteroids, 700 of which are at least half a mile wide. If something that size hit the Earth, "it would cause global climatic catastrophe," said Allan Harris, senior scientist at the Space Science Institute, and one of the foremost authorities on near-Earth asteroids. The dust blown up from the impact would block the sun, causing global crop failure and mass starvation. According to Harris, half the world's population would be "at risk of not making it through the year."

Even a much smaller asteroid could set off massive hurricanes, create tsunami waves or burn large swaths of the planet's surface. Scientists believe a 180-foot-wide asteroid exploded in the atmosphere above the Tunguska forest in Siberia in 1908, flattening every tree for 800 square miles.

Searching for killer asteroids is nothing new for amateur astronomers, but their close collaboration with NASA's top scientists is a recent development. Much of that cooperation is happening on an Internet message group called the Minor Planet Mailing List, which has grown to more than 800 members. The list is run by Richard Kowalski, a 40-year-old baggage handler at US Airways in Florida by day and an astronomer by night.

Like many of the avid amateurs, Kowalski grew up during the space race of the late 1960s and early 1970s, when he formed a lifelong fascination with the cosmos. Whenever there was a mission to the moon, he and his father would spread a 4-foot moon map on the wall and chart its course.

"He took me by the hand and showed me the skies," Kowalski said. "Being able to see the moon and know that people are heading there at that young age made a huge impression in me."

Today, Kowalski observes the skies through a 28-centimer (11-inch), computer-driven telescope. He houses it in a backyard garden shed with a retractable roof. Amateur setups like his can cost as much as $25,000; but, like most amateurs, Kowalski put it together himself, without the benefit of NASA endowments.

Most nights he works the late shift so he can set up his telescope's automation before it gets dark. While he loads luggage onto airplanes, the telescope is busy capturing images deep into space and sometimes making new discoveries.

In 1998, he found a new asteroid, and while Kowalski received no money nor a thank-you call from NASA, he did receive one special honor: He got to name it. Thanks to him, there is a rock flying silently between Mars and Jupiter named Emil, after the now-deceased man who held Kowalski's hand as a little boy and showed him the skies -- his father.

Neil Samson Katz is a student atthe School of Journalism of Columbia University, New York's oldest institution of higher learning