Roy Tucker codiscovered Apophis, an
astroid that has a 1-in-45,000 chance of
striking earth in 2036, with his
backyard telescope.
Image courtesy of Roy Tucker
The likelihood that one of these space rocks poses a real threat to human lives may be low—researchers at Prince-ton University have placed 1-in-5,000 odds on an asteroid two-thirds of a mile across smacking into Earth sometime in the next century (for comparison, the risk that you will be struck by lightning in your lifetime is about 1 in 3,000)—but the stakes are high. A relatively small 150-foot asteroid that struck Tunguska, Siberia, in 1908 packed the punch of 15 million tons of TNT, equivalent to the largest nuclear bomb ever detonated by the United States. Fortunately, it fell far from human habitation. If an asteroid of the size studied by the Princeton researchers struck Europe or the eastern seaboard of the United States, the death toll could run into the millions. “There’s no upper limit on the amount of damage that could occur if a large asteroid were to hit,” says Roy Tucker, an imaging specialist and amateur astronomer in Tucson, Arizona. “Even the boulders that crumble off the surface of big asteroids could cause Tunguska-like events.”
The American government has responded to the threat with funding to allow NASA to seek out potentially threatening asteroids—just barely. NASA supports the Spaceguard survey to the tune of $4.1 million per year, but that sum of money is not enough to cover the cost of continually monitoring all areas of the sky for near-Earth objects. As a result, Representative Dana Rohrabacher of Southern California has introduced congressional bills that would provide monetary awards to amateur astronomers for their contributions to the asteroid hunt. “The near-Earth object threat to our planet is a vital area of concern,” he says. “We can’t just rely on the government to narrow the information gap, so we’re mobilizing our citizens to identify things that might be dangerous.”
From NASA’s point of view, the value of amateurs is obvious: The more pairs of telescope-aided eyes scanning the cosmos, the greater the likelihood that significant discoveries will be made—and given the budget crunches of the past few years, the agency needs all the unpaid sky watchers it can get. More observers in far-flung locations also mean more vantage points, making it easier to calculate the orbit of a stadium-sized asteroid once it is discovered. At the same time, the number of serious amateurs is growing quickly because of new digital CCD light detectors that can make even modest telescopes powerful enough to observe dim asteroids. “A research-quality microscope can cost $100,000, but nowadays a good telescope might be as little as $10,000,” says Steve Chesley, an expert on near-Earth objects at NASA’s Jet Propulsion Laboratory who analyzes the observations of dozens of amateur astronomers.
Over the past decade, scientists like Chesley have routinely turned to hobbyists for help with important but unglamorous tasks like taking several images of an asteroid to plot its trajectory. In return, they give their amateur acquaintances the same respect as colleagues with advanced degrees—for the most part. “There are only a few prima donnas,” Tucker says. Amateurs and professionals are frequently on a first-name basis. “Dear Ron,” reads an e-mail from Chesley in Dyvig’s inbox, “really appreciate all the assistance! Thanks again, Steve.”
As a result, amateur astronomers are playing a crucial role in the search. Two years ago, Tucker helped discover 2004 MN4 (more catchily known as Apophis), an 800-foot-wide asteroid that looked like it might be on course to collide with Earth in 2029.
In principle, asteroid hunting is accessible to anyone with a decent grounding in astronomy and a modest-sized savings account, but in practice it can be a full-time job—one with strange hours and virtually no compensation. Tucker, who has discovered 234 large and small asteroids since 1996, shuts off his alarm clock at 4:15 in the morning, rolls out of bed, and goes outside to put covers on the mirrors of his three 14-inch telescopes. The $12,000 scopes take high-resolution snapshots of one particular strip of sky all night, but their efficacy declines rapidly as dawn creeps over the horizon. By 5:00, Tucker is already in front of his computer, scrutinizing the several hundred digital images his telescopes have just produced for signs an asteroid might be passing through. “I look for streaks,” he says. “Asteroids tend to move very fast relative to everything else.”
