Or, to be very clear about it, once you get to “the planet”, the answer is, “planet and bedrock pull all the other things down by their own planetary gravity, so the gravitational center of mass doesn’t need to be held up by anything”.
Or, to be very clear about it, once you get to “the planet”, the answer is, “planet and bedrock pull all the other things down by their own planetary gravity, so the gravitational center of mass doesn’t need to be held up by anything”.