Uranus

The Sideways Planet
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Planetary Features

Interesting Facts About Uranus

  • Uranus is known as the “sideways planet” because it rotates on its side.
  • Uranus was discovered in 1781 by William Herschel.
  • Uranus was the first planet found using a telescope.
  • Uranus is an Ice Giant planet and nearly four times larger than Earth.
  • Uranus has 27 known moons, most of which are named after literary characters.
  • Like Saturn, Jupiter and Neptune, Uranus is a ringed planet.

The first planet found with the aid of a telescope, Uranus was discovered in 1781 by astronomer William Herschel, although he originally thought it was either a comet or a star.

It was two years later that the object was universally accepted as a new planet, in part because of observations by astronomer Johann Elert Bode. Herschel tried unsuccessfully to name his discovery Georgium Sidus after King George III. Instead the scientific community accepted Bode's suggestion to name it Uranus, the Greek god of the sky, as suggested by Bode.

Go Farther. Explore Uranus In Depth ›

Ten Things to Know About Uranus

10 Need-to-Know Things About Uranus

1

Huge

Uranus is about four times wider than Earth. If Earth were a large apple, Uranus would be the size of a basketball.

2

Seventh Wanderer

Uranus orbits our Sun, a star, and is the seventh planet from the Sun at a distance of about 1.8 billion miles (2.9 billion kilometers).

3

Short-ish Day, Longish Year

Uranus takes about 17 hours to rotate once (a Uranian day), and about 84 Earth years to complete an orbit of the Sun (a Uranian year).

4

Ice Giant

Uranus is an ice giant. Most of its mass is a hot, dense fluid of "icy" materials – water, methane and ammonia – above a small rocky core.

5

Gassy

Uranus has an atmosphere made mostly of molecular hydrogen and atomic helium, with a small amount of methane.

6

Many Moons

Uranus has 27 known moons, and they are named after characters from the works of William Shakespeare and Alexander Pope.

7

The Other Ringed World

Uranus has 13 known rings. The inner rings are narrow and dark and the outer rings are brightly colored.

8

A Bit Lonely

Voyager 2 is the only spacecraft to fly by Uranus. No spacecraft has orbited this distant planet to study it at length and up close.

9

Lifeless

Uranus cannot support life as we know it.

10

One cool fact

Like Venus, Uranus rotates east to west. But Uranus is unique in that it rotates on its side.

Did You Know?

Did You Know?

Uranus' unique sideways rotation makes for weird seasons. The planet's north pole experiences 21 years of nighttime in winter, 21 years of daytime in summer and 42 years of day and night in the spring and fall.

Pop Culture

Pop Culture

Uranus is the "butt" of more than a few jokes and witty (and not so witty) puns, but it's also a frequent destination in various fictional stories, such as the video game Mass Effect and TV shows like Doctor Who. The radioactive element uranium was named after Uranus when it was discovered in 1789, just eight years after the planet was discovered.

Kid-Friendly Uranus

Illustration of Uranus

Kid-Friendly Uranus

Uranus is made of water, methane, and ammonia fluids above a small rocky center. Its atmosphere is made of hydrogen and helium like Jupiter and Saturn, but it also has methane. The methane makes Uranus blue.

Uranus also has faint rings. The inner rings are narrow and dark. The outer rings are brightly colored and easier to see.

Like Venus, Uranus rotates in the opposite direction as most other planets. And unlike any other planet, Uranus rotates on its side.

Visit NASA Space Place for more kid-friendly facts.

NASA Space Place: All About Uranus ›

Resources

Resources

Uranus News