in a few years astroid 99942 Apophis will be passing by at something like 20,000 miles from earth. that is about 1/10th the distance to the moon. It is about 1,100 feet in diameter which I assume is big enough to make a bad day if it were to hit earth.
so what I was wondering is how close could this thing without causing damage. I think it would be pretty cool if it skimmed the atmosphere enough to maybe light up and, most importantly, keep on going back into space.