Uranus


Uranus with its moon Ariel

Uranus, the first planet discovered after the invention of the telescope, is distinct with its light blue color.

It is the seventh planet from the sun and the 3rd largest planet in the solar system. Many do not realize that Uranus is actually visible to the naked eye as long as there are no clouds, no moon, and the sky is very dark.

Uranus is still a mystery to astronomers, but there are no plans to send probes or crafts to the planet any time soon. The pictures and information we do have is from January 1986 when the Voyager 2 flew by.

Distance from Sun

Uranus is a huge 2,870,000,000 kilometers (1,780,000,000 miles from the Sun. That is 19 times further than Earth. The Sun would look very small at that distance, and would provide very little warmth.

 

Size

Uranus is large enough to be able to hold 63 Earths inside of it.

Uranus has 4 times the circumference of Earth, which would change the title of Jules Verne's novel "Around the World in 80 Days" more like "Around the World in 320 Days".

Density

Uranus has only a ¼ of the Earth's density but about 91% of the gravitational pull of Earth.

Example: A person weighing 45 kilograms (100 pounds) would weigh about 41 kilograms (91 pounds) at the equator of Uranus, that is if you could get there, or even stand on the planet, which you can't, as we will see.

Surface

Like the other Gas Giants (Jupiter, Saturn, and Neptune), Uranus is a big ball of gas and ice.

Nothing with any substance could land on Uranus, and would only sink down into the ice core if attempted.

Uranus is made of 85% Hydrogen (H2), 13% Helium (He), and 2% Methane (CH4).

Uranus is a unique color because the methane in the atmosphere absorbs all red light, so any sunlight reflected back to us from the atmosphere will always appear light blue-green.

 

Core

Although no one has been able to see into the core of Uranus, it is thought it might be a large icy rock.

Around the rock is a sea of hydrogen, water, and helium which makes up most of the planet.

 

Cold

Even though it is not the most distant planet from the sun, Uranus is the coldest planet in the solar system and its average temperature is a really cold -216°C (-357°F).

The cold temperature are due to a few factors, one being that the planet does not generate heat.

Unusual Flight Pattern

The cold temperature on Uranus is also thought to be because of the way the planet rotates. Most of the planets rotate counter-clockwise, while Uranus (and Venus also) rotates clockwise, known as retrograde.

Uranus does not have the normal up and down axis of other planets, instead it is tilted on its side. It has been thought that something collided with the planet so hard it knocked it on its side and by doing so discharged much of the planet's internal heat.

Day and Year

One day on Uranus is 17 hours and 14 minutes long.

A year, however, is the length of 84 Earth years.

 


Rings of Uranus

Rings

Like the other Gas Giants, Uranus also has rings surrounding it.

So far, 13 narrow rings have been discovered. The rings are very dark and hard to see.

Moons

Uranus has 27 moons, uniquely named after Shakespearean characters.

Oberon and Titania are the largest moons and were discovered in 1787 by William Herschel.

The third moon Ariel and fourth moon, Umbriel were discovered by William Lassell in 1851. It would not be until 1948 that more moons would be found.

 

 


Mercury, Venus, Earth, Mars,
the Gas Giants Jupiter, Saturn, Uranus and Neptune

(Images courtesy NASA.)