Overall, about 100 tons of space rocks, most the size of sand grains and pebbles, blast through Earth's atmosphere every day.
As asteroid of DA14's size, which is about 150 feet in diameter, wouldn't cause global catastrophe if it did hit like the six-mile wide object that slammed into what is now Mexico’s Yucatan peninsula, triggering climate changes so severe and long-lasting that dinosaurs, among other plant and animal life, vanished some 66 million years ago.
Moving at about 8 miles per second, an object of DA14's size on a collision course with Earth would strike with the force of about 2.4 million tons of dynamite, the equivalent of hundreds of Hiroshima-type bombs.
"They still do a lot of regional destruction," said Lindley Johnson, who oversees the Near-Earth Object Observations Program at NASA headquarters in Washington DC.
In 1908, for example, an asteroid or comet blasted apart as it approached Siberia, destroying 80 million trees over 830 square miles in the process.
DA14 was just discovered last year, though astronomers suspect it has been regularly visiting Earth for some time. The asteroid is smaller than the objects NASA has been tasked to track, though astronomers are making progress on cataloging all the celestial objects that orbit near Earth.
DA14 will be even less likely to harm Earth in the future. Its close encounter on Friday should tweak its orbit so that upcoming encounters will be fewer and farther away.
"The close approach (on Friday) will perturb its orbit so that actually instead of having an orbital period of one year it’ll lose a couple of months," Yeomans told Discovery News.
"We ran it out for 100 years and there is no closer approach in the foreseeable future. The Earth is going to put this one in an orbit that is considerably safer," he said.
