A 150-foot asteroid passed Earth on Friday, the closest known flyby for a rock of its size.
NASA promised the asteroid would miss Earth by 17,150 miles, avoiding catastrophe. There's no word yet if the fly-by affected any nearby communication and weather satellites.
Asteroid 2012 DA14, as it's called, is too small to see with the naked eye even at its closest approach over the Indian Ocean near Sumatra.
The best viewing locations, with binoculars and telescopes, were in Asia, Australia and eastern Europe. Even there, all anyone saw was a pinpoint of light as the asteroid zoomed 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.
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 provided 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.
Humanity has to do better, he said. The foundation is working to build and launch an infrared space telescope to find and track threatening asteroids.
DA14 — discovered by Spanish astronomers last February — is "such a close call" that it is a "celestial torpedo across the bow of spaceship Earth," Schweickart said in a phone interview Thursday.
Astronomers organized asteroid-encounter parties for Friday and experts just about everywhere gave flyby rundowns.
Scientists at NASA's Near-Earth Object program at California's Jet Propulsion Laboratory estimate that an object of this size makes a close approach like this every 40 years. The likelihood of a strike is every 1,200 years.
If a killer asteroid was, indeed, incoming, a spacecraft could be launched to nudge the asteroid out of Earth's way, changing its speed and the point of intersection. A second spacecraft would make a slight alteration in the path of the asteroid and ensure it never intersects with the planet again, Schweickart said.
Of course, this is all in theory.
Forget an asteroid blowup like the one depicted in the 1998 film "Armageddon." The last thing Earth needs is asteroid fragments raining down.
"Thanks, Hollywood," Schweickart said with a laugh.
Learn more on NASA's website: http://www.nasa.gov/topics/solarsystem/features/asteroidflyby.html