universe.applyEvent(new GravityEvent(earth));
universe.applyEvent(new GravityEvent(mercury2));
universe.applyEvent(new GravityEvent(sun));
solvedCollisions.clear();
universe.applyEvent(new CollisionCheckEvent(mercury, solvedCollisions));
universe.applyEvent(new CollisionCheckEvent(earth, solvedCollisions));
universe.applyEvent(new CollisionCheckEvent(mercury2, solvedCollisions));
universe.applyEvent(new CollisionCheckEvent(sun, solvedCollisions));
mercury.update(0.5f);
earth.update(0.5f);
mercury2.update(0.5f);
sun.update(0.5f);