The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

All of our solar system ... the planets appear in the sky, they all appear roughly along the ecliptic. It isn't a perfect line of planets, because their orbits are tilted slightly, but it is fairly ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit ...