Shut your eyes and hope for the best...
If kinetic energy is equal to 1/2 mass * velocity squared, and the mass is a very large lump of rock of god knows what weight, or even more importantly, goodness knows what density relative to its size, and its impact velocity is pretty large (which is a given for any asteroid/celestial object that makes contact with the earths surface) then the resulting impact is going to have a mildy irritating impact on the planets population to say the least.
Now think about how a solar sail, or impulse engine, or rocket or any other of our means of propulsion in space is going to effect said object and its trajectory in space.
Just to give some of you a clue, Force = Mass * Acceleration, and our solar system, and our planets', gravity well will not be helping us, and solar sails and impulse engines take a long time to get going.