Neptune is the eighth planet of the Sun and the most distant planet known in the Solar System. It is also the fourth largest planet, the densest giant planet and the third largest mass. Neptune has a slightly larger mass than its twin planet Uranus and is 17 times the mass of the Earth. It takes about 164.8 years for Neptune to complete its orbit around the Sun at an average distance of astronomical units 30.1. The planet is called Neptune after the Roman god of the sea. It is believed that one of the first recorded observations of Neptune was between 1612 and 1613 through Galileo’s drawings which included traced points depicting what is currently known as Neptune. However, Galileo was not given credit for the discovery of the planet.
The internal composition of Neptune
The internal structure of Neptune is similar to that of Uranus. The planet’s atmosphere forms approximately 5% to 10% of its mass which extends from about 10% to 20% towards the nucleus where the pressure reaches the gigapascals 10 which is about 100,000 times higher than the pressure detected in the earth’s atmosphere. The lower regions of the atmosphere of Neptune consist of increased concentrations of ammonia, water and methane.
The mantle of Neptune
Neptune’s coat is rich in ammonia, methane and water. It is equivalent to between 10 and 15 Earth masses. According to planetary science, this mixture is known as “ice” despite having the characteristics of a hot and dense fluid. Also known as ocean water-ammonia, the fluid is a high conductor of electricity. The mantle can consist of a layer of ionic water that breaks down into oxygen ions and hydrogen soup. Deeper in the mantle there can exist superionic water where the oxygen molecules crystallize and the hydrogen ions float freely within the oxygen mesh. At 4347 miles deep, methane can decompose and rain in the form of diamond crystals like hailstones.
The nucleus of Neptune
The inside of the nucleus of Neptune has a mass of about 1.2 times that of the Earth. It is composed of silicates, nickel and iron. The center of the planet’s core is 700 gigapascals which is about twice as high as that of the Earth, while its temperature can be around 5,400 Kelvin.
The atmosphere of Neptune
Neptune’s atmosphere includes 80% hydrogen and 19% high-altitude helium. It also contains small traces of methane. While methane is responsible for giving the planet its blue tone, astronomers believe that an atmospheric component that remains unknown is the cause of the blue color of Neptune, which is different from that of Uranus. The atmosphere of Neptune is further divided into the stratosphere where the altitude increases with increasing temperatures and in the lower troposphere where the altitude is lower, the temperature is lower. The tropopause is what separates these two regions of the atmosphere at a chilopascal pressure 10. After the stratosphere there are two other layers of the atmosphere: the thermosphere at a pressure between 1 and ten kilopascals and the exosphere.
