Lack of preparation
In hindsight, astronomers say the episode reveals a system not prepared to properly find and evaluate small asteroids that could hit Earth within hours or days of being spotted.
"We were all surprised about what happened," Chapman told SPACE.com.
NASA spends a modest $3.5 million per year as part of the Spaceguard Survey search for large asteroids, the sort that could cause global damage, including a global "winter" that might last years and could kill off some species and possibly threaten civilization. Were one of these objects bigger than 0.6 miles (1 kilometer) found to be on an Earth-impact trajectory, scientists agree the warming time would almost certainly be years or decades.
But very little money is spent to catalogue and process the observational data, which includes the serendipitous discoveries of many small asteroids that could destroy a city or devastate a country. The smaller objects typically go unnoticed until they are very near the planet (and most of them pass by without incident -- were it otherwise you'd know).
Only about 3 or 4 percent of NASA's asteroid spending goes toward follow-up work. The Minor Planet Center, meanwhile, operates on a shoestring budget relying partly on subscriptions to its data mailings.
"For the most part, we had not previously contemplated the possibility of discovery by the Spaceguard Survey of a small asteroid on its final plunge toward Earth," said Morrison, an astrobiologist and asteroid expert at NASA's Ames Research Center. "Indeed, it is exceeding unlikely for such an event to occur."
But low odds don't mean it won't happen tomorrow, or next month.
"If we simply trusted the odds, we would probably pack up and go home, since no impact is likely within our lifetimes," he said. "But it is the possibility of an improbable impact that motivates us."
Within 48 hours of the January scare, Chapman says, the Minor Planet Center made changes to its software so that this precise kind of situation can't happen again. In fact, he notes, a similar scenario arose two weeks later but did not cause alarm.
