NASA scientists 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.
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.
Friday's meteor further strengthened the asteroid-alert message.
"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.
If a killer asteroid was, indeed, incoming, a spacecraft could, in theory, 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.
Asteroid DA14 — discovered by Spanish astronomers only 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.
NASA's deep-space antenna in California's Mojave Desert was ready to collect radar images, but not until eight hours after the closest approach given the United States' poor positioning for the big event.
B612 Foundation: http://b612foundation.org/