From a distance, our solar system looks empty. If you enclosed it within a sphere -- one large enough to contain the orbit of Neptune, the outermost planet -- then the volume occupied by the Sun, all planets, and their moons would take up a little more than one-trillionth the enclosed space. But it's not empty, the space between the planets contains all manner of chunky rocks, pebbles, ice balls, dust, streams of charged particles, and far-flung probes. The space is also permeated by monstrous gravi­tational and magnetic fields

From a distance, our solar system looks empty. If you enclosed it within a sphere -- one large enough to contain the orbit of Neptune, the outermost planet -- then the volume occupied by the Sun, all planets, and their moons would take up a little more than one-trillionth the enclosed space. But it's not empty, the space between the planets contains all manner of chunky rocks, pebbles, ice balls, dust, streams of charged particles, and far-flung probes. The space is also permeated by monstrous gravi­tational and magnetic fields