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Uranus is the seventh planet from the sun in our solar system. This huge, icy planet is covered with clouds and is encircled by a belt of 11 rings and 18 moons. Uranus' blue color is caused by the methane (CH4) in its atmosphere; this molecule absorbs red light.
ROTATIONAL AXIS
Uranus' rotational axis is strongly tilted on its side (97.9°). Instead of rotating with its axis roughly perpendicular to the plane of its orbit (like all the other planets in our Solar System), Uranus rotates on its side (along its orbital path). This tipped rotational axis gives rise to extreme seasons on Uranus.
Because of its almost-perpendicular axis orientation, there is a debate over which of Uranus' poles is its north pole. This debates leads to yet another: Is Uranus spinning in a retrograde orbit (like Venus) or not (like the other planets)?
SIZE
Uranus is about 31,690 miles (51,118 km) in diameter. This is about 4 times the diameter of the Earth.
This gas giant is the third-largest planet in our Solar System (after Jupiter and Saturn).
MASS AND GRAVITY
Uranus' mass is about 8.68 x 1025 kg. This is about 14 times the mass of the Earth. The gravity on Uranus is only 91% of the gravity on Earth. This is because it is such a large planet (and the gravitational force a planet exerts upon an object at the planet's surface is proportional to its mass and to the inverse of its radius squared).
A 100-pound person on Uranus would weigh 91 pounds.
LENGTH OF A DAY AND YEAR ON URANUS
Each day on Uranus takes 17.9 Earth hours. A year on Uranus takes 84.07 Earth years; it takes 84.07 Earth years for Uranus to orbit the sun once.
URANUS' ORBIT AND DISTANCE FROM THE SUN
Uranus is over 19 times as far from the Sun as the Earth is; it averages 19.18 A.U.
At aphelion (the farthest point in its solar orbit) it is 1,850,000,000 miles (3,003,000,000 km) from the Sun. At perihelion (the closest point in its solar orbit) it is 1,700,000,000 miles (2,739,000,000 km) from the Sun.
TEMPERATURE
The mean temperature on the surface of Uranus' cloud layer is -350°F (59 K). Uranus radiates very little heat in comparison with the other gas giants, Jupiter, Saturn, and Neptune).
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