Uranus

The oddest thing about Uranus is that the planet, its rings, and its moons "roll" around the Sun on an axis tilted by more than 90 degrees. The other planets orbit more like spinning tops with their axis pointed more straight up and down. This planet's surface is hidden from our view by a thick layer of cold smog.

Diameter: 32,000 miles Location>: 7th planet from Sun Number of Moons: 17
Average Distance from Sun: 1.8 billion miles
First observed: 1781
Cloud Top Temperature: -320 degrees F
Orbital period: 84 Earth years
Characteristics: atmosphere made of methane, helium, and hydrogen; has a core of silicate rock; blue-green appearance caused by clouds of methane ice crystals

Image credits: courtesy of NASA; Frank Summers: AMNH.