The asteroid is estimated to measure between 187 and 426 feet, or 57 to 130 meters, across. It was discovered by scientists from Brazil and the United States only within days of its passing. Because it approached from the direction of the sun it was hard to spot. If it had made impact, it would have hit the planet with 30 times the power of the atomic bomb that destroyed Hiroshima. While the impact would have been large, it would not have been a global event. Scientists call it a “city-killer” asteroid because the estimated possible impact. They had not been tracking the asteroid, and described it as appearing from “out of nowhere.”
At this time, the world’s asteroid-finding infrastructure isn’t able to complete even the 140-meter goal, according to a National Academies report released earlier this year. “We missed this object because we miss most objects in this size range,” Amy Mainzer, principal investigator of NEOWISE asteroid-hunting space telescope, told to media. Mainzer said that astronomers must continue tracking objects like this in order to better determine their orbits to see whether they pose a threat.