This estimate was alarming; it was the first time an asteroid had been promoted to "Level 4" on the Torino Scale -- a near-Earth object (NEO) impact hazard categorization method.

这样的预测令人担忧，这是在评价近地天体（NEO）撞击危险程度的 “托里诺分类表”（THE TORINO IMPACT HAZARD SCALE）中第一次有小行星进入“4级”（译注：该分类表最高为10级）。

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Such asteroids come along perhaps once every 100, 000 years or more, according to the scale, called the Torino Hazard Impact Scale.

CNN: Scientists reduce odds of Earth-asteroid collision