Iowa Alumni Magazine | February 2007 | Features

Planet Protector

By Kathryn Howe
Hold onto your asteroid belts! A pioneering professor says we need to pay attention to IFOs (Identified Flying Objects).

Star-studded skies still captivate Michael Gaffey, one of the world's leading experts on planetary-asteroid collision.

The celestial diamonds glittered coldly in the night skies. Above the tiny northern Iowa hamlet of Riceville, population 800, endless stars sprawled across a vast arc of darkness to inspire a young boy's dreams of the heavens.

As he walked the lonely gravel roads near this farming town, little Michael Gaffey sought entertainment and wonder in spectacular views of the solar system—a welcome diversion from the daily routine of household chores and minding eight younger brothers and sisters. Other times, he found amusement below his feet in the interesting shapes and formations of scattered rocks.

In an isolated place like Riceville, stars and rocks were keys to adventure, the staples of a country kid's toy box. Only, Gaffey never outgrew his enthusiasm for such interests. Thanks in part to his admiration for the University of Iowa's famous physicist James Van Allen, 36MS, 39PhD, he chose to study geology and astronomy in Iowa City. And for that, perhaps we should thank our lucky stars.

Childhood fascinations don't often turn into world-renowned research that quite literally could save the world. But that's what happened for Gaffey, now a space sciences professor at the University of North Dakota.

Basically, Gaffey hunts asteroids. Specifically, he studies ways to prevent them from smashing into Earth, sending humankind the way of the dinosaurs. While such an idea may seem fantastic, the possibility looms closer than many of us might like to think. "Objects have crashed into our planet for the entire age of the solar system," says Gaffey, 68BA, 79MS, who most definitely looks the part of a scientist—a jolly one at that—with an unruly beard and bright, curious eyes. "Eventually, a significant asteroid will crash into us again. It's just a matter of time."

Rocky and metallic objects left over from the formation of the universe about 4.6 billion years ago, asteroids range in size from the 565-mile-diameter Ceres to mere pebbles. Most of them, including the giant Ceres, revolve around the Sun in an orderly elliptical pattern within a main belt between the orbits of Mars and Jupiter. Occasionally, however—thanks to Jupiter's mighty gravitational pull or close encounters with other nearby objects—they stray from their paths and cross the orbits of other planets, including Earth.

The most pressing threat for us is a 1,049-foot asteroid that's expected to come within about 14,000 miles of Earth in 2029. Though scientists have calculated that the object will miss us at that time, they worry that Earth's gravitational pull could alter its orbit, increasing the likelihood of a collision when the asteroid zooms past once again in 2036. If a direct hit does occur, it's difficult to predict the consequences, as the damage an asteroid can cause largely depends on its makeup and velocity. While it's unlikely that this particular asteroid would affect Earth on a global scale, a devastating tsunami and nuclear-like explosion at the impact site rank among the stark possibilities.

Should such a devastating asteroid fall from the sky right now, there's not much we could do to avert a crisis. Our space sciences arsenal is pretty much empty. By 2036, though, effective technologies could be available. That's the purpose behind Gaffey's work—to have remedies in place so humankind has a fighting chance if the worst-case scenario plays out. A major catastrophe probably won't happen tomorrow or even in our lifetime, but scientists know the threat to future generations is a frightening reality.

The good news is that asteroid collision is one of the few natural disasters that can be anticipated years in advance and potentially controlled.

"Luckily, Earth is an itty-bitty target in an expansive area of space, and most asteroids pass by safely," says Gaffey. "We're concerned with those that might not. We want to take care of them before they become a hazard."

Gaffey's main interests lie in identifying the material composition of these space rocks that sometimes careen around the solar system as if inside an enormous pinball machine. Armed with this information, his colleagues can better decide how to thwart the asteroids that bounce into Earth's neighborhood.

While the fruits of his research may be many years distant, Gaffey's already received recognition for his important endeavors. In 2006, he became only the second person in history to accept the two most prestigious awards in his field—the G.K. Gilbert Award and Leonard Medal—in the same year.

Despite such international accolades and the lofty nature of his preoccupations, this space man remains remarkably down to earth. He struggles to see himself in the same category as other Gilbert and Leonard recipients, scientists whose names the public may not recognize but who nevertheless are the most accomplished leaders in their fields. "I feel slightly embarrassed to be included in that crowd," he says. "I keep thinking I'll wake up and someone will tell me I have to give the awards back."

About 150 researchers worldwide investigate the problem of asteroid collision. Chiefly, these specialists work to detect, characterize, and manage the trajectory of "near-Earth objects"—the more than 4,000 known asteroids and comets that enter or cross the orbit of Earth and could eventually come close enough to strike us. At the moment, they're nearing the end of a federally mandated project to assess the potential hazards of all near-Earth objects larger than 5/8 of a mile. Circulating around the solar system are between 1.1 and 1.9 million such asteroids with the potential to cause an explosive force of 50,000 megatons — equivalent to twice the arsenal of atomic weapons held by the U.S. and Soviet Union at the peak of the Cold War.

Just how close is a near-Earth object? Scientists consider anything that comes within 1.2 million miles of our planet a potential problem. In galactic terms, that's only a few cat whiskers away from catastrophe.

Experts believe wayward asteroids have crashed into Earth on many occasions, in some cases altering the geological and evolutionary destiny of the planet. Researchers link the extinction of the dinosaurs 65 million years ago to a devastating impact on the Yucat‡n peninsula in Mexico. That asteroid was estimated at 6.2 miles in diameter and released energy on the order of 30 million megatons of TNT. While experts can't say exactly why the dinosaurs perished, they point to a direct causal relationship between that impact and the eventual environmental meltdown that destroyed the species.

Other examples include the early crash of a Mars-size object into the 100 million-year-old Earth that sent chunks of planetary debris hurtling across space to ultimately form our moon. Another colossal impact in Southeast Asia 770,000 years ago melted soil into black fragments of glass, ejecting millions of tons of molten rock across one-tenth of Earth's surface.

One of the best preserved exhibits of contact is the Barringer Meteor Crater near Winslow, Arizona, which resulted 50,000 years ago from a dense 150-foot object traveling at the speed of 28,600 miles per hour. The explosion created by this impact proved 150 times the force of the atomic bomb that destroyed Hiroshima.

To stave off future fire and brimstone, Gaffey and fellow scientists tackle their enormous task in three ways. Firstly, as requested by Congress, they pinpoint where the enemies lurk in space. Secondly, they chart asteroids' size and composition, because a giant object made of iron requires a different solution than a smaller one consisting of mud and ice. Finally, they try to devise ways to slow, destroy, or alter the orbit of an approaching threat. Gaffey's expertise in the second step of this process dates back to his days as a doctoral student at the Massachusetts Institute of Technology (see sidebar), where he pioneered a method that used reflected light off meteorites to study their composition.

With their combined knowledge, researchers have proposed two missions to test different prevention strategies aimed at deflecting the orbits of asteroids. In 2011, the European Space Agency's "Don Quijote" project will launch the spacecrafts Sancho and Hidalgo to place radar reflectors on an asteroid, slam into it, and measure any changes in its path. By 2015, American researchers working on a project called "B-612" (named after the asteroid in Antoine de Saint Exupery's popular children's book The Little Prince) hope to send a spacecraft to attach an engine to a small asteroid. The engine will push on the mass for several months, while scientists note any effect on orbit.

A new round of congressional funding will enable the study of all near-Earth objects greater than 460 feet in diameter. While people tend to think of asteroid collision in terms of global environmental catastrophe, Gaffey explains that smaller threats could deliver severe local and regional devastation. A 460-foot object made of nickel or iron could release 1,000 megatons of energy, create a 1.2-mile crater (toasting all living creatures located near the rim), and spark a massive earthquake. Even a 2,600-foot mud-and-ice ball that disintegrates in the atmosphere could inflict painful third-degree burns on every living thing within a 180-mile radius.

Although government research dollars flow now, Gaffey points out that, prior to 1994, Capitol Hill paid scant attention to the study of near-Earth objects, and only a handful of scientists really searched for them. The wake-up call came when a comet slammed into Jupiter that year, creating a fireball larger than Earth. This phenomenon stirred fears in lawmakers, who soon gave their full attention to what they'd dismissed as science fiction. Researchers have since been scrambling to amass information about these dangerous objects. Now, with NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California, and several other search programs receiving $3 to $4 million each year, the number of discoveries has skyrocketed from a mere 350 to thousands—with the list growing every month.

Asteroid work consumes most of his days, but Gaffey also finds time for other, related academic pursuits. The scientific societies that presented Gaffey his two recent awards also cited him for the strides he's made in understanding the nature of meteorites, the only pristine material left over from the formation of the inner solar system. Through this research, Gaffey hopes to unravel the mysteries of the early years of the universe and the history of Earth.

"Meteorites offer important clues about what the universe might've looked like at the very beginning," says Gaffey. "What we know about these early days is like reading War and Peace but with 700 pages ripped out. I've always been fascinated by the origins of things. I want to know what went on. It's like putting a puzzle together.

"This may have no commercial value, but some of the highest things we do as humans don't. As a species, we are what we learn. Understanding the universe—even if it doesn't pay us back—that's what we do. Meteorites tell us the story, and it's a fun story to read."

Gaffey also studies space mining—the notion that the universe's resources can make space travel more cost-efficient, opening the door for human settlement of distant worlds. At the University of North Dakota, he teaches one of only a few classes in the country on this subject. As a result, he's trained some of the field's leading experts, who look at ways to curb the costs of space travel through possibilities such as harvesting water from the moon. A gallon of water may cost only $1, Gaffey explains, but it requires hundreds of thousands of dollars to transport it to the International Space Station, let alone to the moon or Mars.

Whether or not an asteroid does ever smash into our planet, Gaffey firmly believes the future of the human race depends on moving skyward. "We can be certain that, about four to five billion years from now, the Sun will turn into a red giant and Earth will disappear," he says. "All that we've accomplished and hold dear is temporary as long as we leave it here."

Gaffey knows he won't be around to witness the realization of this prediction. He may never see the day when the world calls upon his work to protect the only home we've ever known. But he still loves to look up at the night sky and wonder at the possibilities in each shining star.