Small amounts of force applied in any direction will not set the Earth into a collision course with the Sun. An intuitive explanation for why can be found in th

Small amounts of force applied in any direction will not set the Earth into a collision course with the Sun. An intuitive explanation for why can be found in the game Osmos. www.osmos-game.com The short reason is that inertia is the entire reason the Earth is orbiting the Sun right now, you have to overcome that inertia rather than generate more of it. When you're playing Osmos during the orbital sections, a little bit of playing around reveals that the best way to reduce your orbit is to thrust in the same direction you're currently moving in. To increase your orbit, you thrust in the opposite direction. Thrusting towards or away from the 'star' alters your orbit somewhat but doesn't really change how far away from the star you are on average. After awhile you figure out the right way to finesse your way into orbits that carry you on a trajectory to eat smaller bodies. With that skill comes the dying off of the fantasy of being able to easily dispatch the Earth in this fashion. Inertia doesn't work that way.