n 1994, the Jovian crash of comet Shoemaker-Levy 9 provided astronomers with a spectacular illustration of the pyrotechnics that can occur when celestial debris collides with a planet. Although scientists acknowledge that the chances of a similar object hitting Earth remain remote, they are nonetheless vigilant in their attempts to forewarn humanity of a comparable terrestrial strike.
Asteroid and Comet Impact Hazards is part of those attempts, a primarily text-based Web site that imparts information on practically every facet of the comets and asteroids that cross Earth orbit. Along with a fairly detailed introduction that examines the threat of a collision, the site offers congressional comments regarding Near Earth Objects (NEOs) and the need to discover potential methods of predicting and avoiding catastrophic crashes.
The site also highlights various news stories, including one outlining the formation of a NASA office devoted specifically to studying NEO data. A number of reports concerning celestial impact hazards are posted, along with a detailed list of the known bodies that pass through or near Earth's orbit. A basic reference bibliography is available too, as are reviews of recent non-fiction books on the subject, a brief fact sheet, links to additional Web sites and a small art gallery featuring pictorial representations of various collisions.
Separating science fact from science fiction
While numerous science fiction books and films have made the threat of a comet or asteroid crash seem simultaneously alarming and alluring, the information on this site leaves readers with a significantly more sobering impression of such a scenario. According to the fact sheet, only about 10 percent of the estimated 2,000 NEOs have even been discovered, and a cursory examination of the television miniseries Asteroid shows that, while clearly unrealistic, in some respects the screenplay actually understates the devastating effects of a collision.
At first glance, the extended list of objects that cross Earth's path is a bit dreary, presenting rows of numbers that appear both daunting and dizzying. Closer inspection soon reveals a lode of intriguing data describing such things as distance and orbital arc, and though in some sections it helps to know Atens from Amors, the roster presents an eye-opening introduction to the sheer quantity of possible planetary pileups.
The links page also offers marvelous insight into the efforts of various organizations to discover and monitor NEOs. Connections to groups such as Spaceguard UK, The Spacewatch Project and The Space Shield Foundation allow individuals to further explore impact phenomena. Overall Asteriod and Comet Impact Hazards is an intriguing site featuring worthwhile information that, although occasionally presented in a tedious manner, serves as a marvelous tool to separate scientific fact from science fiction.
