See also a Flash animation called ‘Keeping An Eye on Space Rocks’ at http://www.jpl.nasa.gov/templates/flash/neo/neo.htm

How would you like to discover a near-Earth object without leaving your own
backyard? It’s possible. On July 2, 2000, amateur astronomer and public
schoolteacher Leonard L. Amburgey stumbled upon the near-Earth asteroid 2000
NM using a modest telescope in his backyard in Fitchburg, Mass. Amburgey
became the fourth winner of the James Benson Prize for Discovery Methods of
Near-Earth Objects by Amateurs. The first amateur to win the cash prize was
Arizona resident Roy Tucker, who found an Earth-orbit crossing asteroid from
his backyard using a Celestron 14-inch telescope and a self-designed camera.

“There are some very sophisticated amateur astronomers out there and we rely
upon them to help monitor the future motions of Earth-approaching comets and
asteroids,” said Dr. Don Yeomans, JPL manager of NASA’s Near-Earth Object
Program Office.

Amateur astronomers are making a big difference in helping NASA keep an eye
on the comets and asteroids that can get close to Earth. While
NASA-supported professional astronomers discover the vast majority of
near-Earth asteroids, amateur astronomers provide many of the follow-up
observations needed to pinpoint the orbits and predict the future motions of
the asteroids. Once a new near-Earth asteroid is discovered, the efficiency
with which amateurs provide these follow-up observations allows larger
professional telescope facilities to continue scanning the skies for more
new discoveries.

The study of near-Earth objects is not only important for monitoring
Earth-threatening objects, but also for understanding how the solar system
formed from these bodies. Comets are the leftover bits and pieces from the
formation of the outer solar system, which occurred some 4.6 billion years
ago. Asteroids are the debris left from the inner solar system formation
process. Comets and asteroids are also important because they brought to the
early Earth some of the water and carbon-based molecules from which life
formed.

But how does one discover a near-Earth object?

The most successful near-Earth object hunters are those who can scan large
areas of dark sky each night with large aperture telescopes. Some amateur
astronomers, like Bill Yeung, are able to set up their own private
observatories. Yeung, who discovered his first 15 asteroids by renting a 16″
telescope that was a 2-hour drive away from his home in Canada, now observes
the sky with several powerful telescopes running each night at his Desert
Eagle Observatory in Benson, Ariz. He has made 1732 asteroid discoveries,
including the object recently identified as J002E3 that turned out to be an
Apollo 12 rocket stage. This discovery is highlighted on the JPL Near-Earth
Object Program Office Web page at: http://neo.jpl.nasa.gov .

Most asteroids are discovered when their motions, relative to the fixed
background of stars, give them away. Professional telescopic surveys can
capture images of a particular region of sky three or more times several
minutes apart. These images are compared to see if any bright “stars” are
actually moving, revealing them as potential near-Earth objects. Amateur
astronomers study the variations in the amount of sunlight that asteroids
reflect as they rotate in space. Based on these observations, astronomers
can determine the asteroid’s rotation period and often the orientation of
its rotation axis in space. They can also infer certain characteristics of
the asteroid, such as its size and shape.

Amateur astronomers are particularly adept at discovering comets. Comets
appear fuzzy when their ices vaporize near the Sun, releasing dust particles
that reflect sunlight. Amateur astronomers have been very successful in
discovering some of the brighter comets by scanning the skies for fuzzy
bright spots in the twilight and pre-dawn skies. The most recent impressive
comet (Hale-Bopp), seen in the spring of 1997, was discovered by two amateur
astronomers, Alan Hale and Thomas Bopp.

One area where amateur astronomers have outdone the professionals is in
discovering near-Sun comets. Using digital images of a region of space near
the Sun provided in near-real time on the Internet by the Solar and
Heliospheric Observatory project, amateur astronomers have actually
identified several hundred “kamikaze” comets. These tiny icy comets, most of
which are fragments from a once larger comet, destroy themselves as they
plunge toward the solar inferno.

What do I do if I find a near-Earth object?

Should an amateur astronomer make an asteroid or comet finding, they should
contact the Minor Planet Center, part of the Smithsonian Astrophysical
Observatory at the Harvard-Smithsonian Center for Astrophysics in Cambridge,
Mass. The Minor Planet Center makes the observations provided by the entire
international astronomical community available to orbit determination
centers such as JPL’s Near-Earth Object Program Office. Using these
observations, professional astronomers can compute the near-Earth object’s
orbit and predict its future motion.

The purpose of the Near-Earth Object Program is to coordinate NASA-sponsored
efforts to detect, track and characterize potentially hazardous asteroids
and comets that could approach the Earth. The program will focus on the goal
of locating at least 90 percent of the estimated 1,000 asteroids that
approach the Earth and are larger than 1 kilometer (about two-thirds of a
mile) in diameter, by the end of 2008. In addition to helping coordinate the
detection and cataloging of near-Earth objects, the Near-Earth Object
Program Office will be responsible for facilitating communications between
the astronomical community and the public should any potentially hazardous
objects be discovered.

JPL is a division of the California Institute of Technology in Pasadena,
California.