Planet Nine sits on the edge of our solar system, roughly 100 billion miles from our Sun. Until we see the planet with our own eyes, we won't know much about its surface. One theory is that Planet 9 is rocky like Earth, but 10 times as massive.
Planet Nine sits on the edge of our solar system, roughly 100 billion miles from our Sun. Until we see the planet with our own eyes, we won't know much about its surface. One theory is that Planet 9 is rocky like Earth, but 10 times as massive.