Hit parade

Natural History, Sept, 2003 by Robert (American businessman and engineer) Anderson

Meteorites are no longer the rare objects I once imagined them to be. The realization came to me soon after I began searching the Internet for information about them, and found Bill Arnett's "The Nine Planets" (www.nineplanets. org). Under the heading "Small Bodies," click on "Meteors, Meteorites and Impacts" for a quick rundown on the subject and a great list of links. At the link www.solarviews. com/eng/edu/micromet.htm, I was surprised to learn how easy it is to collect these extraterrestrial visitors by the hundreds.

I immediately went outside my home with a ladder and scooped up some of the fine silt that accumulates in my roof's rain gutters. My son helped me extract the iron bits from the dirt with a magnet, and voila! We soon had a tiny pile of metallic particles to examine under a microscope lens. We discovered a number of good candidates for micrometeorites--primordial space dust that literally rains down on our roof. Another site, "Micrometeorite Webquest" (staff.harrisonburg.k12.va.us/~gcorder/mm_main.html), explains how to collect the celestial specimens directly from rainwater. Click on the hypertext "images" to get some idea of the size and shape of the objects my son and I were looking for.

Not surprisingly, meteoroids that create fireballs as they plunge through the atmosphere are more exciting to most people. Scroll all the way down the meteor page at "The Nine Planets," cited above, and under the heading "Impacts," click on "The Peekskill Fireball" (starchild.gsfc.nasa.gov/docs/StarChild/ shadow/solar_system_level2/peekskill. html) to see a movie of one of the more spectacular events of its kind. Recorded in 1992, the fireball first appeared over West Virginia and broke up as it traveled. A sizable chunk of it crashed into a parked red Chevrolet Malibu coupe in the town of Peekskill, New York. You can see a piece of the famous specimen at "The R.A. Langheinrich Museum of Meteorites" (nyrockman.com/museum. htm). A link there will even take you to several photographs of the impacted Malibu.

You'll find an impressive list of links to sites that highlight comets and the asteroid belt--the source of most of the meteoroids that enter Earth's atmosphere--at NASA's "National Space Science Data Center" (go to nssdc.gsfc.nasa.gov/ planetary/planets/ and click on "Asteroids and Comets"). Such giant asteroids as Vesta--the only asteroid from which terrestrial meteorites have been identified to date--are featured there

In spite of Hollywood's disaster-movie infatuation five years ago with colossal comet and asteroid impacts, public interest in the theme has waned. Unfortunately, the danger hasn't. But at another NASA Web site (go to impact.arc.nasa.gov/ and click on "OECD Report on NEO Hazard"), you'll find a report noting that an impact might be averted, given early enough warning. A complete guide for close-encounter paranoids can be found at NASA's "Near-Earth Object Program" (neo.jpl.nasa.gov), an excellent fount of NEO information of all kinds. Click on "Close Approaches" in the list on the left to see exactly how near the Earth some NEOs will approach in the future, and how close some have come in the recent past--a sobering experience.

Robert Anderson is a freelance science writer living in Los Angeles.