parallel to the plane of Uranus’s orbit, so that the poles point toward the Sun. Scientists believe the peculiar inclination may have resulted from a collision, in the early days of the solar system, with an object the size of Earth.
    Because of its distance from the Sun, Uranus receives only a small fraction as much solar energy as the Earth. The average temperature in the outer portions of the atmosphere is about 59 degrees Kelvin, more than 200 degrees below the freezing point of water. 
    The planet’s structure is quite different from the rocky planets (Mercury, Venus, Earth, and Mars) and even from Jupiter and Saturn. Uranus is believed to have a rocky core, very hot at the center, which