Due to my job and other classes, I've been studying ahead of my class by myself to not fall behind and I'm not sure if I'm oversimplifying this in my head and not really grasping the idea. Newton's First Law of Motion states that an object with a net force of zero stays in constant motion (or rest). So, if an object appears to be accelerating, there must be a net force acting on it. The way I understand it, if I were to get in my car and accelerate to some object A, that object A would appear to be accelerating towards me, even though there isn't a force acting on it, and this is why Newton's First Law doesn't apply to accelerating reference frames. Am I oversimplifying this? While I can understand how objects would seem to accelerate due to an accelerating reference frame and you wouldn't want that, what particularly confuses me is that we use the earth as a reference frame yet the earth accelerates around the sun. Are we just using the earth as a good enough approximation of an inertial reference frame? Would it be correct in thinking that there isn't an absolute inertial reference frame?