In 30 minutes, the earth will have a 4.4 million-mile rendezvous with a large asteroid.

The moon is a quarter million miles from earth, and the asteroid which will pass by us at 8:05 AM will be 4.4 away. So, that is not really a close call. Or is it? It depends how you view it. Yes, other asteroids have come a lot closer. I recall one in the late 1980s which passed between the moon and earth and which was not even detected until it after it made its way on through. However, this morning's visiting asteroid is a lot bigger than that one was. At three miles wide, the asteroid, named Florence, would pose a threat to earth life if she collided with our planet. Fortunately, that will not be the case. Even more fortunate is that, in the coming decades and beyond, earth will probably not be hit by a life-ending asteroid.l

http://www.cnn.com/2017/08/31/us/asteroid-florence-earth-fly-by-trnd/index.html