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What is Uranus Made Of?

Shashank Nakate Jul 14, 2020
It took a lot of research and time for astronomers to answer the question,"What is Uranus made Of?" The commonly accepted, standard model of Uranus known to us is formed of three layers. Find more on the topic through this write-up.
Uranus, which is the seventh planet in our solar system, was discovered on 13th March, 1781 by William Herschel. And this faraway planet took time to reveal the answer to, "What is Uranus made Of?", which is explored here in brief. Atmosphere of Uranus is the coldest of all the planets of our solar system.
The main components of Uranus are ammonia, water and methane. The minimum temperature reached by this coldest planet is -224°C. Density of Uranus is 1.27g/cm3. Total mass of this planet is 14.5 times that of the Earth; its mass is 8.68 x 10^25 kg. Uranus doesn't have a hard surface like other planets. This is because its outer layer is gaseous.

Composition of Uranus

Uranus is composed of three layers. The outer layer is gaseous, middle layer is formed of ice and the innermost layer is hard and rocky - composed of iron-nickle/silicates.

• The middle layer forms bulk of the planet. Although it is known as the ice layer - a dense and hot mixture of ammonia - water and other substances are also present in the middle layer.
• Water clouds present in Uranus form the lower layers of atmosphere. The main component of upper layers of Uranus is methane. The icy mantle of Uranus is referred as water-ammonia.

• Mass of the inner portion of Uranus is just 0.55% of the earth's mass. Density of the central core of Uranus is 9 g/cm3 and its temperature is 5000 K.
• The atmosphere of Uranus is composed of molecular helium and hydrogen. The percentage of hydrogen (H2) and Helium (He) in the atmosphere of Uranus is 83 +/- 3% and 15 +/- 3% respectively.
• The helium molar fraction in upper troposphere is 0.15 +/- 0.03; the value is close to 0.275 +/- 0.01 (the protosolar helium mass fraction).
This shows that the central portion of Uranus doesn't have helium settled in it. Hydrogen deuteride (HD) forms a small portion (0.007-0.015%) of Uranus.

• Cloud structure of troposphere is complex. Water clouds are present in the plane/at a place in the troposphere where pressure ranges from 50-100 bar. The percentage of methane in Uranus' atmosphere is 2.3%.
• The stratosphere of Uranus contains traces of different kinds of hydrocarbons. Ultra-violet rays emitted by the Sun causes photolysis of methane, which results into formation of hydrocarbons. The ionosphere of Uranus is denser than that of Neptune and Saturn.
• The three-layered model of Uranus is considered as the standard one. However, many different models, based on varying observations, have been proposed.

Facts About Uranus

The facts about Uranus provide some useful and interesting details about its structure and composition.
• Uranus gets its unique, bluish color from methane. The red light absorbed by methane gets reflected as blue light.
• Different layers of Uranus are known to blend seamlessly. These layers are not separated by a clear/well-defined border.
• The poles of Uranus are tilted to such a degree that they almost face the Sun directly. Due to rapid rotation of Uranus, storms with a speed of 600 km/hr are formed on this planet.
• Images captured by the spaceship, Voyager 2 didn't reveal anything new or significant about planet Uranus. However, it is important to note that increased weather activity and other signs of seasonal change have been observed in recent years. Changes were also witnessed by terrestrial observers at the time of equinox of Uranus.

Rings of Uranus

The rings of Uranus are 13 in number and they are composed of dust and other macroscopic particles. Since the rings are dark-colored, their Geometric Albedo and Bond Albedo values are 0.51 and 0.3 respectively.
It is difficult to say with authority about the exact chemical composition of Uranus rings. The rings of Uranus may be composed of organic compounds; these organic compounds appear dark due to radiations emitted from magnetosphere of Uranus.

Geometric Albedo

The geometric albedo is calculated for astronomical bodies. It is the ratio of brightness of an astronomical body at zero angle phase to brightness of a perfectly reflecting body of the same size which 'diffusely' reflects light.

Bond Albedo

The bond albedo value, just like geometric albedo, is calculated for an astronomical body. Bond albedo is a portion or fraction of power in the light (electromagnetic radiation) which scatters in the space after it gets reflected from an astronomical body.
Uranus can be deemed one of the weirdest planets of our solar system owing to its highly tilted axis and other interesting characteristics. The facts and information presented above, should give us a fair idea of the composition of Uranus.