Would a 200 meter diameter meteor destroy earth?
No, however its effects would be substantial. The asteroid which is currently considered to be the greatest danger to earth is 1950 DA, which is approximatley 1-1.5km in diameter. If 1950 DA were to strike earth it is estimated that the impact would be roughly equivelent to a 100,000 megaton explosion. 1950 DA is not expected to approach earth until 2880.
