Asteroid watch: Watch out for a close encounter with an asteroid on Feb. 1, 2019. How close? That’s the big question. The space rock, designated as 2002 NT7, was discovered July 9 by the LINEAR asteroid-watching program — and astronomers believe the object is more than a mile (2 kilometers) wide. That’s big enough to spark a mass extinction, if 2002 NT7 were to hit Earth.
On the basis of the first observations, scientists have calculated an extremely inclined orbital path that crosses close to Earth’s path several times between now and 2078. The highest risk comes in 2019: There’s roughly one chance in several hundred thousand that Earth will be hit, NASA estimates.
NASA says the risk is a little bit lower than the “background level” — that is, the random risk posed by the entire range of near-Earth objects. However, an Italian analysis group known as NEODyS currently estimates the impact risk as higher than the background level — at a little better than 1 in 100,000.
Donald Yeomans, the head of NASA’s Near Earth Objects Program, says more observations are needed to nail down the orbit more precisely. “It is something that bears watching. ... (But) this is not something to get concerned about,” he says. “If anything, it’s just an indication that the system is working.”
Yeomans says 2002 NT7 is significant because it’s so big, and because it does come relatively close to Earth’s orbit. For those reasons, the results so far have been reviewed by the International Astronomical Union, he says. However, in every earlier case, further observations narrowed down the risk to virtually zero.
“This one, I’m guessing, will hang around where it is for a few more weeks,” he says, “and then, as the orbit gets better and better, it’ll disappear from this page.”