Uranus Basics

Quick Facts

Average Distance from Sun: 
1,783,000,000 miles 
(2,871,000,000 kilometers)
19.2 AU

Length of Year: 
84 years, 4 days

Length of Day: 
17 hours, 14 minutes

Diameter at Equator: 
31,750 miles  (51,120 kilometers)

Mass: 
 14.5 times Earth

Surface Temperature (in upper atmosphere):
-360¡F  (-220¡C)

Introduction

    Uranus is the seventh planet from the Sun.  It is the third largest planet in the solar system.  Only Jupiter and Saturn are larger.  Uranus's diameter is more than four times larger than Earth's.  If Earth were the size of the ball used in playing Jacks, Uranus would be the size of a cantaloupe.

    Uranus is one of the five outer planets.  The others are Jupiter, Saturn, Neptune, and Pluto.  Uranus is very far away.  It can't be seen without a telescope.  Uranus wasn't discovered until 1781.  It was the first planet discovered with a telescope.    Uranus, Jupiter, Saturn, and Neptune are all gas giants.  Gas giants are much larger than Earth.  They do not have solid surfaces.  They do have deep gaseous atmospheres.  Uranus and Neptune have even more in common.  Both planets are about the same size.  They are covered with clouds of a similar color.  They are also much smaller than either Jupiter or Saturn.

    Uranus has 15 moons.  The moons are icy.  Several have cut and battered surfaces.  The planet is surrounded by thin rings.  The rings weren't discovered until 1977.

    There is one thing very different about Uranus.  It is tipped over almost on its side.


Compared to Earth

    Uranus is a large planet.  Its diameter is more than four times the diameter of Earth.  About 64 planets the size of Earth could fit inside Uranus.

    Uranus has a very large core.  Uranus's core is bigger than Earth.  It takes up over one quarter of the planet's diameter.  Earth's inner and outer cores take up over half of Earth's diameter.    Uranus has a liquid mantle.  It takes up a little more than two fifths of the planet's diameter.  Earth's rocky mantle is just under half its diameter.  Above Earth's mantle is a thin crust.  Uranus has no crust at all.  Above its mantle is a deep atmosphere.  This gas layer takes up just under one third of the planet's diameter.  Earth's atmosphere is very thin by comparison.

    Uranus is larger than Earth.  It doesn't have a lot of mass for its size though.  So, its surface gravity is a little less than Earth's.  A person who weighs 100 pounds (45 kg) on Earth would weigh about 79 pounds (41 kg) on Uranus.   Uranus doesn't have a solid surface.  The weight is calculated as if you were standing at the top of its clouds.  Move the slider below to compare weights.   The slider shows weight in pounds.

    Uranus is over 19 times farther from the Sun than Earth is.  It takes sunlight 2 hours and 40 minutes to reach the planet.  It takes only 8 minutes for sunlight to reach Earth.  Uranus is so far from the Sun, it receives very little of the Sun's heat.  This makes Uranus an extremely cold planet.  The average temperature at the cloud tops is -360¡F (-220¡C).