The Asteroid Hunter
New Mexico scientist searches the skies for signs of ‘killer’ asteroids
Asteroid: Amateur astronomers helping NASA
As a kid, Eileen Ryan always liked the 1970s science-fiction movies where a disheveled guy in a lab coat would
show up at the last minute and save the planet from giant spiders and other threats.
These days, Ryan is an accomplished astronomer at the New Mexico Institute of Mining and Technology who is helping NASA figure out which asteroids might hit the planet, potentially wiping out a major city or worse. The International Astronomical Union has named an asteroid after her, (9542) ERYAN, and she specializes in figuring out ways to blow them up.
But Ryan, 47, has no plans to show up anywhere at the last minute to save the planet from a giant asteroid. She wants to know years in advance.
Due to NASA’s budget constraints, Ryan, along with a legion of amateur and professional astronomers, help keep the space agency abreast of what’s shaking in the orbits.
NASA runs a program that detects, tracks, catalogues and characterizes near-Earth objects that are 460 feet in diameter or larger (think of The Pit at The University of New Mexico, although it is a little smaller) and within 120 million miles of the sun. Near-Earth objects include comets and asteroids. In simple terms, an asteroid is a comet without a tail.
By 2020, the program is supposed to have 90 percent of the survey done. But a report to Congress in March says that goal is unrealistic given the agency’s $4.1 million annual budget for the program and should be modified to track and characterize objects of the same size within 4.6 million miles of Earth’s orbit. The Earth is about 93 million miles from the sun.
If an asteroid 460 feet in diameter hit Earth, it would produce problems on a regional level, according to NASA. An asteroid
1,000 feet in diameter could harm countries, and one 3,280 feet in diameter — or one kilometer — could produce global problems.
If an asteroid that is 32,808 feet in diameter — or 10 kilometers — hit Earth, it could cause life forms to become extinct, similar to the asteroid that many scientists believe caused dinosaurs to become extinct. An asteroid
10 kilometers in diameter would be roughly the size of the city of Santa Fe, minus the far south side.
In addition to the initial catastrophe created if an asteroid hit a populated area of the Earth, particles generated from the impact would likely cause environmental problems by blocking out sunlight, Ryan said.
Ryan, who is the project scientist and manager of the new Magdalena Ridge Observatory near Socorro, has been pinpointing and describing asteroids for more than 20 years. The
$11 million observatory opened this spring, and Ryan said she plans to use the 2.4-meter telescope to track asteroids. Before the big telescope was available, she frequently used a regular 14-inch telescope.
Ryan says she is one of many people who use smaller telescopes to help the government track asteroids.
Don Yeomans, a team manager of NASA’s near-Earth object project, said there is a whole community of amateur and professional astronomers like Ryan who are helping with the project. Some use telescopes as small as six or eight inches. The task for many amateurs is to simply find asteroids, and more experienced astronomers like Ryan determine the orbit, shape, size and composition of asteroids, Yeomans said.
"It’s not sufficient to just discover the objects," he said. "We have to follow through and determine their orbits to see where they travel."
Many people active in helping track asteroids subscribe to the Minor Planet Mailing List, which allows people to post information about objects in space, Yeomans said.
Throughout the world,
asteroids have caused about
330 known craters on Earth, but there are probably many more that people haven’t discovered yet or are hidden under the oceans, Ryan said.
"It’s truly a problem," she said. "We have to worry about these things because we don’t know. We have to prepare for any outcome."
In addition to helping NASA track asteroids, Ryan is also contributing information about how to deal with an asteroid should one ever come hurtling toward Earth. She conducts research by using computer models and laboratory experiments with rocks and bullets.
There are two big challenges when it comes to blowing up asteroids, Ryan said. The first is that many of them are shaped like dog bones or other odd shapes, which means it would be difficult to hit the asteroid at one specific point and blow it up, Ryan said.
The second challenge is that many asteroids aren’t one solid mass, Ryan said. Instead, they have hit other objects in space and broken up, so they’re essentially rubble piles, Ryan said.
Trying to break up one of the rubble-pile asteroids with an explosive would be like trying to break up a lump of mashed potatoes with a bullet, Ryan said. Instead of breaking up the mashed potatoes, the bullet would go right through and merely create a hole, she said.
The concern with both scenarios is that attacking an asteroid with an explosive device could make a situation worse, Ryan said.
The purpose of striking an asteroid with an explosive device would be to break it up into small enough pieces that it would burn up in the Earth’s atmosphere, Ryan said. But if an explosive device turned an asteroid into pieces too large to break up in the Earth’s atmosphere, the problem could be just as bad or worse, she said.
The situation is comparable to deciding whether it is better to be hit with one bullet from a .45-caliber pistol or many pieces from a shotgun blast, she said.
"A smaller asteroid wouldn’t cause a global catastrophe, but it could decimate a city," Ryan said.
It would be easier for scientists to disrupt the orbit of an asteroid that was farther away, Ryan said, but if an asteroid is closer, it would be more likely that scientists would have to blow it up.
According to a NASA report on near-Earth objects in March, the agency says it would either try to deflect an asteroid or blow it up into small pieces that would burn up in the Earth’s atmosphere.
Possibilities for deflecting an asteroid include using a large mirror to focus solar energy on an asteroid and boiling off material, or positioning a spacecraft near an asteroid and using a laser to boil off material, according to the report.
The government could also use a spacecraft to attach mining material to an asteroid and eject material from the asteroid at a high velocity, the report says, or use a spacecraft to literally push it out of the Earth’s path.
To dismantle an asteroid, NASA says using a nuclear-armed missile would be more effective than a conventional explosive. The study team looked at conventional explosives but found they would be ineffective in most situations.
If the government decided to use a nuclear device, however, it would likely require international coordination because of the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, the report says.
In the meantime, Ryan said she is excited about using the Magdalena Ridge Observatory to continue her research. The observatory is located at an elevation of 10,600 feet on a mountain ridge outside of Socorro. Getting there takes about an hour and requires a four-wheel-drive vehicle to navigate the one-lane road, which can be muddy and slippery in spots.
Ryan said most observatories are located on top of mountains — a fact she learned the hard way when she started her career as an astronomer.
Ryan said she grew up in suburban New Jersey, where all the roads are paved. The first time fellow students drove her to the top of a mountain-top observatory in the Southwest as a graduate student, she thought they must be pulling a trick on her because of the extremely rugged terrain, she said.
The Magdalena Ridge telescope, which is housed beneath a big dome that opens to reveal the heavens, has three basic missions, Ryan said. It’s there for scientists to use for classic astronomical research, to help the federal Department of Defense conduct space surveillance, track missiles and sense remote satellites, as well as support educational and public outreach.
Contractors installed the telescope in September 2006, Ryan said, and scientists have been testing it since then. She hopes to be able to use it more often for research this summer.
The building in which the telescope is located includes a kitchen, a bathroom with a shower, and two bedrooms so scientists and other visitors can stay for a few days if necessary.
The facilities also include a bank of computers that can help scientists track information.
There are no known asteroids currently on track to hit Earth, Ryan said. But since craters all over the Earth show that asteroid collisions are a fact of life, one is likely to hit at some point, somewhere, she said.
In the meantime, Ryan said she doesn’t have to worry about the asteroid named after her — (9542) ERYAN — crashing into Earth because the International Astronomical Union only names asteroids that have no chance of hitting the Earth.
The union allows asteroid discoverers to name asteroids, and Ted Bowell, a colleague of hers when she worked in Arizona, discovered (9542) ERYAN in 1983 and named it after Ryan in 1998 because of her contributions to asteroid characterization studies, Ryan said. By then, she had finished her doctoral degree in planetary geophysics from the University of Arizona and she was teaching physics at New Mexico Highlands University in Las Vegas, N.M., with her husband, William Ryan, who is an astronomer at New Mexico Tech these days.
"It’s a great honor to be recognized," she said.