Killer asteroids
先写下记得的内容，再查看解释。不要填写个人信息。
查看解释
No known significant threat is a qualified claim: it refers to what is known and what counts as significant in that report. It does not mean every object has been discovered or that every possible future impact is ruled out. Read the surrounding time frame and assessment.
Space agencies confirm no known significant asteroid threat for the next hundred years.