This is something I haven't been able to wrap my head around yet. In physics, I've always been told that gravity is a force that ALWAYS works between "objects" with mass. Now, it seems clear to me that if a feather and a hammer were to be dropped at the same time on earth (without air resistance doing work on the two objects) they would indeed fall at the same velocity. Here is my problem: if gravity works between all objects, and if "insert planet or object" pulls with a greater force on the heavier object, to compensate for the heavier mass, wouldn't the object also pull on the "insert planet or object"? Let's say you have a planet with the weight of 6,0 * 10^20 kg. You drop two objects: a feather (with the weight 0,1 kg) and a gigantic ball (with the weight 6,0 * 10^19 kg. Given that the two objects are only affected by gravity, why won't the big ball (with a mass almost equal to the planet's mass) pull the planet closer to itself, thus reaching impact before the feather does? I love physics, and I just recently started taking classes in high school. Any answers are greatly appreciated.