If somehow a massive object, let's say 3e5kg, was accelerated to a relativistic velocity and it blows by earth at 0.9c a few hundred km above the surface of the earth, what happens? At that speed, it clearly has enough energy to warp spacetime; would it have a noticeable effect here on earth? Theoretically, couldn't a relatively small object be traveling with enough energy to throw us off of our oribt? I'm roughly thinking of it like an impulse problem considering the time it would have to influence us would be minimal at best. I guess this is akin to the "a gnat can stop a train with enough speed" kind of question.