When you think about the nine planets, which one comes to mind first? More than likely you’re probably thinking of either Mars or Jupiter. Why not Uranus? For obvious reasons, the planet is not very popular. For one thing, there hasn’t been a spacecraft sent there since January 1986, when Voyager 2 passed by the planet. If in the near future, an orbiter makes the first attempt in circling the planet, it would endure the intense heat of the thermosphere and stratosphere. Who knows, it might become covered in blue!
Here on Earth we have five layers of atmosphere: the exosphere, thermosphere, mesosphere, stratosphere, troposphere. However, Uranus only contains three layers of atmosphere. The thermosphere, or the outermost layer, absorbs solar energy and is heated to surging levels of 850K. That’s nearly four times the temperature here! This heat is shared with the middle layer, or stratosphere. As you travel down to the troposphere, you would notice a great decrease in temperature levels. Instead of holding intense heat, a lot of other processes determine the temperature in the troposphere: including water clouds, ammonium hydrosulfide clouds, zonal winds, and seasonal change.
The stratosphere is also responsible for the turquoise color surrounding the planet. As the heat from the thermosphere flows through the stratosphere it ignites the methane, splitting and separating it.
The elements inside of Uranus’ atmosphere are greatly different from the elements inside of Earth’s atmosphere. Earth’s atmosphere contains oxygen, nitrogen, argon and carbon dioxide, which are not found on Uranus. Below are two pie charts showing the composition of Uranus’ and Earth’s atmospheres. Since Uranus does not contain oxygen and nitrogen we would not be able to live on the planet. It’s a possibility that the gases on the planet would allow a spacecraft or an orbiter to travel through, but they may also be flammable.
Atmosphere of Uranus vs. Earth
Top: This pie chart shows the primary elements in Uranus’ atmosphere and the percentage of the atmosphere they make up. There are, however, other traces of elements such as water vapor, carbon dioxide and carbon monoxide etc. Bottom: This is a pie chart of the Earth’s atmosphere. Oxygen makes up 21% of the atmosphere, Nitrogen 78%, Carbon dioxide 0.03%, Argon 1%, all others 0.1% (Earth’s pie chart from http://www.ux1.eiu.edu/~cfjps/1400/atmos_origin.html)
Have you heard of the Hindenburg Disaster of 1937? As the blimp made a last attempt in landing in its harbor, it exploded due to friction of hydrogen and oxygen. One of Uranus’ primary elements is hydrogen. If a spacecraft filled with oxygen traveled through the atmosphere, the friction between the two elements may cause an explosion, which would make the planet dangerous for human life. If a spacecraft were to enter the planet, it would need to be made from something other than oxygen or any element that may cause an explosion.
Uranus has many components that have not been explored since 1986. What new discoveries will we find if we visit again? Perhaps something that will make you think of Uranus first when considering the planets.