Cosmic fly-by


The heavenly object has a humdrum name: Asteroid 2012 DA14. The 150-foot-long mass will come within 17,200 miles of Earth’s surface on Friday.

That’s closer than any similar-sized asteroid has gotten without crashing into the planet, as far as scientists know. It is one of 500,000 asteroids in the immediate cosmic neighborhood, NASA says.

Traveling at a pokey (for outer space) 4.8 miles per second, the asteroid will get close enough to Earth to have its orbit subtly shifted. It will speed up before it is sent scurrying around the sun with 51 days shaved from its usual 368-day orbital period, thanks to Earth’s gravitational field. Humans won’t see it again until 2110, if all goes well.

Among objects of such size that get this close to Earth, the asteroid is a once-in-40-years event. Usually, there’s a major asteroid collision with Earth every 1,200 years. Scientists don’t expect that to happen this week.

If it does, it won’t destroy the planet. But the asteroid could do major damage to a reasonably sized city. If it crashes into an ocean, expect tsunamis and tidal waves.

The technology for spotting asteroids and plotting their trajectory has gotten so reliable in recent years that it is hard to sneak them past scientists anymore. Amateur astronomers in southern Spain discovered this asteroid last year.

They’ll watch expectantly as the space mass gets within kissing distance of Earth. This is one hot-and-heavy close encounter our planet can do without.