Artist's concept showing how Uranus might look from a position in space several hundred thousand miles above its south pole. Uranus is a gas giant composed primarily of hydrogen and helium gases surrounding a relatively small, dense core of molten rock and metal. Its bluish color is due to the presence of methane in its upper atmosphere. Uranus also has a ring system. However, Uranus' rings are over three orders of magnitude dimmer than Saturn's; where Saturn's rings are nearly white, Uranus' rings are more like the color of charcoal. One bizarre aspect of Uranus is that its axis of rotation is tipped beyond 90 degrees in relation to the plane of its orbit around the Sun. This puts Uranus' north and south poles, relative to the Sun, where the other planets have their equators.