Here's the full press release from UA about the two-meter diameter asteroid that will hit the atmosphere over northern Sudan at 7:45 p.m. MST tonight:
University of Arizona scientists last night discovered a very small asteroid [right, circled in purple. Go to the Catalina Sky Survey to see a set of time lapse photos - "Discovery Images" - showing the object moving quickly across the sky] that is on course to hit Earth tonight in northern Sudan at about 7:45 p.m. MST.
The asteroid is too small to be hazardous. But it is the first time astronomers have discovered an object with a nearly 100 percent chance of hitting the Earth.
The tiny space rock is only two meters in diameter and is traveling at 12 kilometers per second, said Ed Beshore of the UA's Catalina Sky Survey. "Whether it will survive entry through Earth's atmosphere depends on its composition, " Beshore said. "But it is sure to create a spectacular sight for those fortunate enough to see it at night."
The asteroid is expected to release about one kiloton of energy, either in a single shot or in a series of explosions, when it hits Earth's atmosphere. It is on course to hit Earth's atmosphere with a grazing strike, much like a skipping stone on water, rather than make a direct hit, Beshore said.
"It's probably important for people in that area of the world to know that this is not anything other than a natural phenomenon," Beshore said. "We're all watching pretty closely."
The Jet Propulsion Laboratory's Near Earth Object observations program carefully monitors observations from surveys like Catalina as well as those from individual observers. From this data researchers can determine orbits and the likelihood of a collision with the Earth.
Richard Kowalski, a member of the Catalina Sky Survey team, discovered the object with their 60-inch telescope on Mount Lemmon in the Santa Catalina Mountains north of Tucson.
Amateur Italian astronomers are well positioned to see the impact and may get pictures of it tonight, he added.
Roughly one out of every 20 asteroids is iron, so this one is probably a stony asteroid, Beshore said. Even if this asteroid is iron and reaches the ground intact, the predicted impact area is largely uninhabited, and the danger to individuals is small.
The Catalina Sky Survey last year broke all records for discoveries of near-Earth objects, or NEOs. The survey found more than 450 NEOs in 2007.