Let us ask what makes a planet round? Is it just luck? Or is it logic? The answer is logic. The round shape indicates a perfect balance; the distance of any point on the surface of a sphere and the center is always even from all sides. But is evenness important? Yes, evenness is balance and the laws of physics are the laws of balance in physical nature. Let us ask what causes gravity? Matter or Space? Both.
But does space even exist? Yes, it's got a sub-material existence. Though it's half-real it has an important role to play: gravity. The parts and pieces of planets are held together by space. Read all about the author's ideas in this interesting science and philosophy essay.