CAPE CANAVERAL, Fla. -- A 150-foot asteroid hurtled toward Earth's backyard, destined Friday to make the closest known flyby for a rock of its size.
NASA promised the asteroid would miss Earth by 17,150 miles, avoiding catastrophe. But that's still closer than many communication and weather satellites; scientists insisted these, too, would be spared.
Asteroid 2012 DA14, as it's called, is too small to see with the naked eye even at its closest approach around 2:25 p.m. EST, over the Indian Ocean near Sumatra.
The best viewing locations, with binoculars and telescopes, are in Asia, Australia and eastern Europe. Even there, all anyone can see is a pinpoint of light as the asteroid zooms by at 17,400 mph.
As asteroids go, DA14 is a shrimp. The one that wiped out the dinosaurs 65 million years ago was 6 miles across. But this rock could still do immense damage if it struck, releasing the energy equivalent of 2.4 million tons of TNT and wiping out 750 square miles.
Scientists are certain it won't impact Earth. And chances are extremely remote it will run into any of the satellites orbiting 22,300 miles up.
Most of the solar system's asteroids are situated in a belt between the orbits of Mars and Jupiter, and remain stable there for billions of years. Some occasionally pop out, though, into Earth's neighborhood.
The flyby provides a rare learning opportunity for scientists eager to keep future asteroids at bay - and a prime-time advertisement for those anxious to step up preventive measures.
"We are in a shooting gallery and this is graphic evidence of it," said former Apollo astronaut Rusty Schweickart, chairman emeritus of the B612 Foundation, committed to protecting Earth from dangerous asteroids.
Schweickart noted that 500,000 to 1 million sizable near-Earth objects - asteroids or comets - are out there. Yet less than 1 percent - fewer than 10,000 - have been inventoried.