18 fascinating facts about planet Uranus

| Uranus Facts Table |

Mass (1024 kg ): 


86.8

Volume (1012 km^3): 


68,334.36

Equatorial Diameter (km):


51,118

Polar Diameter (km):


49,946

Age of the Planet: 


4.5 billion years

Number of Moons: 


27

Surface Temperature Range : 


(-218 °C ~ -153 °C)

Average Surface Temperature: 


-195 °C

Gravity (m/s2):


8.7

Day Length (hours):


17.2

Average Distance from Sun (106 km):


2,872.5

Closest Distance to Sun (Perihelion) (106 km):


2,741.3

Furthest Distance from Sun (Aphelion) (106 km):


3,003.6

Orbit Length: 


17,974 million km

Orbiting velocity (km/h):


24,480

Time to Orbit the Sun (Orbital Period): 


83.8 Earth's year

Actual Color: 


Pale blue

Appearance Color: 


Pale blue

Atmosphere Thickness:


Around 50,000 km from the surface

Axial Tilt Angle (degrees):


97.77

Time for Sunlight to the planet:

2 hours and 40 minutes

Magnetic field:

Exist

Ring system: 


Exist

Uranus is a gas giant planet composed of water, methane, and ammonia fluids above a small rocky center. It is the seventh planet from the Sun and is almost 20 times farther from the Sun than Earth. Not only is Uranus greater in its distance from the dwarf star at the center of our solar system, but greater in size: Uranus is 4 times wider than Earth. 

Uranus, on which a year is equivalent to an average human’s lifetime, orbits the Sun once every 84 years. During this long year, Uranus experiences the most extreme seasons in the solar system due to its radical tilt of 97.77 degrees. Such an unusually severe angle is most likely the result of a collision between an Earth-sized object and Uranus.

 

Keep reading to discover the most interesting facts about Uranus.

Uranus Planet

1. Uranus experiences the most extreme seasons in the solar system.

The planet of Uranus is tilted at an extreme angle of 97.77 degrees making it the only planet in the solar system to possess an equator that is nearly at a right angle to its orbit. A year on Uranus, which equals 84 years on Earth, consists of 42 years of sunlight followed by 42 years of darkness on each of its poles.

2. No spacecraft can pass through Uranus's atmosphere.

Uranus produces such extreme pressure and temperatures that it is capable of destroying objects, including metal spacecrafts that dare to venture into its atmosphere. Moreover, Uranus is one of the two planets in our solar system categorized as an ice giant (the other one being Neptune). Being so, Uranus is not endowed with a true surface, so even if a spacecraft were somehow able to make it through the Uranian atmosphere, it would have nowhere to land.

3. To date, only one spacecraft has flown by Uranus.

Voyager 2 is the only spacecraft in history to have flown by Uranus. It did so during its journey to study all four of solar system’s giant planets (Saturn, Jupiter, Uranus, and Neptune).

4. What caused Uranus’ dramatic axial tilt? Scientists posit that the reason why Uranus nearly spins on its side is because it once collided with an Earth-sized object.

Uranus is the only planet in the solar system that has an axial tilt of 97.77 degrees. Scientists theorize that such a unique tilt is the result of a big collision that once occurred between Uranus planet and an Earth-sized object.

5. Uranus's magnetosphere extends for millions of kilometers.

Uranus' magnetosphere
Credit: NASA

Beyond Uranus, beyond the Sun, Uranus’s magnetic field extends into space for millions of kilometers.

Interested in learning more? Check out “How do magnetospheres protect planets from harmful space radiation?

6. 80% of Uranus’s mass is made up of a hot dense fluid composed of icy materials.

A hot dense fluid of icy materials – including water, methane, and ammonia – forms around 80% of Uranus’s mass (excluding Uranus’s small rocky core).

7. ethane gas gives Uranus its pale blue appearance.

When sunlight journeys through Uranus’s atmosphere, methane gas absorbs the red portion of light and reflects the blue portion back into space, leaving the planet with the blue-green color.

8. Uranus is one of the two planets that rotate in the opposite direction (Retrograde Rotation).

Besides Venus, Uranus is the only planet in our solar system to rotate in the opposite direction of the Sun. Earth, and all of the other planets in our solar system, rotate from east to west.

9. Uranus was the first planet to be discovered with the aid of telescopes.

William Herschel discovered Uranus in 1781. Initially, he did not recognize Uranus as a planet, but instead, thought it to be a comet or star. After two years of investigation, Uranus came to be universally accepted as a planet. 

Herschel tried to name the planet “Georgium Sidus” after King George III, but ultimately, it was entitled “Uranus” at the suggestion of astronomer Johann Elert Bode.[1]  

10. Uranus is four times wider than Earth.

With a diameter of 31,700 miles (51,000 km), Uranus is four times wider than Earth, which has a diameter of 8,080 miles (13,000 km).

11. Uranus’s mass is almost 15 times greater than Earth’s mass.

Uranus’s mass equals 191 x 1024 lbs (86.8 x 1024 kg). This is exactly 14.5 times heavier than Earth, which has a mass of 13.2 x 1024 lbs (5.97 x 1024 kg).

12. Uranus has 13 distinct rings.

Uranus has 13 rings in total which are divided into two ring systems: the inner ring system and the outer ring system. The inner ring system is comprised of narrow, dark rings that are grey in color. It is more difficult to see the inner ring system than the outer ring system, which is significantly brighter and vibrantly colored. The innermost ring of the outer ring system is reddish in color while the outermost ring is blue. Starting with the ring that is closest to Uranus and moving outward, Uranus’s rings include Zeta, 6, 5, 4, Alpha, Beta, Eta, Gamma, Delta, Lambda, Epsilon, Nu, and Mu. These rings are positioned at a distance of 24,000 miles (38,000 km) – 61,000 miles (98,000 km) from the center of Uranus.

13. 27 known moons orbit Uranus.

When the Greeks and Romans first observed the various moons in our solar system, they endowed them with a number of different names from Callisto (a moon of Jupiter) to Janus (a moon of Saturn). However, the moons of Uranus did not receive their names from the Greeks nor the Romans, but rather were named after the characters of William Shakespeare and Alexander Pope. Although the first of Uranus’s moons to be discovered (Titania and Oberon) were identified in 1787, some of Uranus’s moons remain mysterious; scientists still have questions about Uranus’s moons, especially concerning the composition of the planet’s outer moons. Though these questions still demand answers, there is much that scientists have come to discover about Uranus’s moons through consistent research over time, such as the fact that all of Uranus’s inner moons are roughly comprised of ice and rock at a ratio of 1:1.

14. Winds on Uranus can reach up to 560 mph (900 km/h).

Winds on Uranus move in two different directions. At its equator, winds move in a retrograde direction (the opposite direction as the planet’s rotation). In contrast, winds which transpire at Uranus’s poles move in a prograde direction (the same direction as the planet’s rotation).

15. A day on Uranus lasts 17 hours and 14 minutes.

Uranus takes 17 hours 14 minutes to complete a full spin around its axis (one day on Uranus).

16. Uranus completes an orbit around the Sun once every 84 Earth years.

Uranus orbits the Sun at a velocity of 15,200 mph (24,480 km/h). Due to its distant location from the Sun and its relatively low velocity compared with planets that are in closer proximity, it takes around 84 Earth years for Uranus to orbit the Sun just once. In 2033, Uranus will have completed its third orbit around the Sun since its discovery in 1781.

17. Light takes 2 hours and 40 minutes to travel from the Sun to Uranus.

Uranus is located 1,784 million miles (2,872.5 million km) away, on average, from the Sun. With light moving at a speed of  0.186 million miles/s (0.3 million km/s) , sunlight needs an average of 9,575 seconds (2 hours, 39 minutes, and 35 Seconds) to reach Uranus.

 

  • At Perihelion (where Uranus is at its closest position relative to the Sun), the distance between the Sun and Uranus is 1,703 million miles (2741.3 million km), which means that sunlight requires 9,138 seconds (2 hours, 32 minutes, and 18 Seconds) to reach Uranus’s surface.
  • At Aphelion (where Uranus is at its farthest position relative to the Sun), the distance between the Sun and Uranus equals 1,866 million miles (3003.6 million km), which means that sunlight requires 10,012 seconds (2 hours, 46 minutes, and 52 Seconds) to reach Uranus’s surface.

In summary, the Sun’s light takes a relatively long time to travel to Uranus; requiring a range of 2 hours, 32 minutes, and 18 seconds to 2 hours, 46 minutes, and 52 seconds depending on the planet’s position in relation to the Sun. On the other hand, it only takes an average of 8 minutes and 20 seconds for sunlight to reach the surface of our home planet: Earth.

18. Uranus’s core temperature can reach 4,982 degrees Celsius.

Uranus’s core has a radius that makes up less than 20% of its total radius, and a mass that is equivalent to only 0.55 of Earth’s mass. Its core heats up to 9,000 degrees Fahrenheit (4,982 degrees Celsius), which is nearly the same as the Sun’s surface temperature.

The photo below shows a detailed comparison of the structures of all the giant planets in our solar system (which include Jupiter, Saturn, Uranus, and Neptune).

Giant planets structure

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