To a first-order approximation, and from far enough away, a collision with the Earth is a collision with the Solar System. Our motion within the Solar System i

To a first-order approximation, and from far enough away, a collision with the Earth is a collision with the Solar System. Our motion within the Solar System is relatively small if the asteroid is a very long way away; it's easy to find scenarios where a fast moving asteroid will appear stationary over a 6 month period.