A planet’s obliquity—the tilt of its axis to its orbital plane—is a major factor in determining the prominence of its seasons. (Recall from Chapter 2 that Earth’s obliquity of 23.5° is responsible for its distinct seasons.) The obliquities of the giant planets are shown in Table 10.1. With an obliquity of only 3°, Jupiter has almost no seasons at all. The obliquities of Saturn and Neptune are slightly larger than those of Earth or Mars. As a result, these two giant planets have moderate but well-defined seasons. Curiously, Uranus spins on an axis that lies nearly in the plane of its orbit. Viewed from Earth, the planet appears to be either spinning face on to Earth or rolling along on its side (or something in between), depending on where Uranus happens to be in its orbit.