Tilted at 98°, Uranus seems to be spinning on its side. As it moves in its orbit, first one pole and then the other points straight at the Sun. Uranus is the third-largest planet, a gas giant with 11 narrow rings.
Table 10. URANUS DATA
|Diameter (width) at equator||31,764 miles (51,118 km)|
|Average distance from Sun||1.784 billion miles (2.871 billion km)|
|Time to orbit Sun||84 years|
|Time to spin around own axis||17.24 hours|
|Mass||14.5 x Earth’s mass|
|Gravity||0.89 x Earth’s gravity|
|Cloudtop temperature||–322°F (–197°C)|
|Number of moons||21|
In 1781, English astronomer William Herschel spied Uranus through his homemade telescope. It was the first planet to be discovered with a telescope.
Uranus has at least 21 moons, and most of them are tiny. Titania, 981 miles (1,578 km) across, is the biggest, and Stephano, roughly 12 miles (20 km) across, the smallest. Most of the moons are named after characters from Shakespeare.