Home | Business News | Browse by Publication | T | The Magazine of Fantasy and Science Fiction

Rocks in space.

Article Excerpt
ON November 20, 2007, Andrea Boattini of the University of Arizona's Catalina Sky Survey spotted an extremely faint object moving across the stars. The story of that object--an Apollo asteroid named 2007WD5--had the makings of a science fiction thriller. Unfortunately for fans of conventional thriller structure (a form marked by mounting tension), most of the story was over by the time Boattini discovered WD5.

Every four years this asteroid--a rock measuring about fifty meters in diameter--drops in from the asteroid belt to cross the Earth's orbit. On November 1, 2007, WD5 had zipped by the Earth at a distance of 7.5 million kilometers, just thirty times farther away than the Moon--a near miss by astronomical standards.

In any thriller worth its salt, one hair's-breadth escape is quickly followed by another. Shortly after Boattini spotted WD5, astronomers at NASA's Near Earth Object program realized that this asteroid was going to pass very close to Mars on its return to the asteroid belt. In fact, there was a chance that the asteroid might collide with the planet--exciting news for anyone interested in cratering and planetary impacts. If WD5 hit Mars, scientists estimated it would make a crater about a kilometer in diameter and 200 meters deep. High-resolution orbiting cameras circling Mars were poised to provide a ringside seat to the aftermath of the impact.

When news of the possible impact went out, the Exploratorium in San Francisco sprang into action, preparing to create a webcast of the impact if it happened. Alas (for the Exploratorium, astronomers, and disaster enthusiasts everywhere), the asteroid passed close to--but missed colliding with--Mars on January 30, 2008. WD5 passed so close to Mars that the asteroid's orbit was disturbed by the gravitational interaction. Astronomers have lost track of WD5 for now, but they expect that it will return in four years.

But we're not willing to wait four years to share all the research Paul did about what happens when an asteroid bashes into a planet. Scientists and science fiction writers are both in the business of asking "What would happen if ...?" In this case, we'll take a look at what would have happened if WD5 had struck the Earth or Mars.

BELLY FLOPS AND ASTEROID IMPACTS

If you've read Robert Heinlein's The Moon is a Harsh Mistress, you already know that an asteroid hitting the Earth will mess things up in the immediate vicinity of the impact. In that novel, moon colonists use a catapult to "throw rocks"--really big rocks--at the Earth.

But if you're like us, you're curious about exactly how destructive that impact will be. We can help you there. The level of destruction depends on three factors: what makes up the asteroid, how big it is, and how fast it's traveling.

Natural objects that are likely to strike a planet come in three major flavors: ice, iron, and stone. Each type of object behaves differently on hitting the planet's atmosphere, if it has one. We'll start close to home...

View this article FREE - Now for a Limited Time, try Goliath Business News
Free for 3 Days!