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Top 10 Facts About Uranus


Since Uranus is visible to the naked eye, it has been observed for millennia, but wasn't known to be a planet until the late 1700s. Below are the top 10 facts about Uranus, the beautiful icy-gas giant.

1. Uranus is the Farthest Planet from Earth that is Visible to the Naked Eye.

Rim Of Uranus
Space Frontiers - Stringer/Archive Photos/Getty Images

Only Neptune orbits at a greater distnace from the Earth, and that world was discovered not by direct observation (though Neptune is easily seen through a telescope) but by analyzing "wobbles" in Uranus' orbit.

2. Uranus can be Pronounced Two Different Ways.


Most commonly the word Uranus is pronounced ū·rā′·nəs (said like "your anus", emphasis placed on the second syllable) which always seems to get a giggle. For this reason, most in academia have taken to pronouncing it ūr′·ə·nəs (said like "urine iss", emphasis on the first syllable). Either way is acceptable, but when around children, or those that act like children, the latter pronunciation is a safer bet.

3. Uranus is the 4th most massive planet in our solar system.


With a mass of approximately 8.6810 × 1025 kg (about 14.5 Earths), the planet Uranus lags behind Jupiter, Saturn and Neptune in terms of mass.

4. Uranus is the 3rd largest planet in our solar system.

At 25,559 ± 4 km (about 4 Earth Radii), Uranus is larger than every planet except Jupiter and Saturn. However, since it is less massive than Neptune, it is not very dense; trailing all other planets except Saturn in terms of density.

5. Uranus actually has rings, though they are hard to see.

The rings of Saturn are well known. But as it happens, all of the Jovian planets (Jupiter, Saturn, Uranus and Neptune) have rings. However, they are generally very difficult to see and require specialized instruments to study. They are generally made from small pieces of ice, rock and dust that are held in orbit by the planet's immense gravity.

6. Uranus is the 7th planet from the Sun.

Despite efforts from some to get Ceres, effectively a large spheroidal asteroid between Mars and Jupiter, classified as a planet, the number of planets in our solar system is static. So after Mercury, Venus, Earth, Mars, Jupiter and Saturn, Uranus is the 7th planet from the Sun.

7. Uranus has at least 27 moons.

All of the Jovian planets (Jupiter, Saturn, Uranus and Neptune) have large numbers of moons. Some of them are very small, asteroid sized objects that are difficult to detect. So the exact number of moons is unknown, but at this time 27 are known to exist.

8. Uranus was named for the Greek God of the sky.

Though many names were suggested for the planet, including Herschel after its discoverer, the logical choice of Uranus was chosen. The reason being, that Saturn is the name for the father of Jupiter, so it makes sense that the next planet out should be the father of Saturn, which is Uranus.

9. While known about for centuries, Uranus was thought to be a star until 1781.

Because Uranus is so far from Earth, it doesn't move very quickly in the night sky. Therefore many early astronomers thought that it was a star. Even later observers, including its "discoverer" William Herschel thought it might be a comet instead. However, it was later correctly determined by Herschel and others in 1781 to be a planet.

10. Uranus nearly "rolls" along its orbit.

With a axis tilt of about 97.7 degrees, Uranus rolls on its side as it orbits around the Sun. This is highly unusual, and only one other planetary-like object, Pluto, is known to rotate in this manner.

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