[blam]

I wonder if this may have 'fallen off' the asteroid that just flew by earth. Can we expect more?

[RightWhale]

Good point. The asteroid was possibly not a solitary body, but part of a swarm like burned-out comets.

[Black Powder]

I wonder if this may have 'fallen off' the asteroid that just flew by earth. Can we expect more?

The Earth picks up about 100 tons of dust/debris from space each day, so this is not a big deal. The girl happened to be lucky that day.