Physical Science:

Neptune [Figure 12.1.9] is the eighth planet and farthest planet from the Sun, and is also an ice giant planet like Uranus. It is named after the Roman god of the sea due to its blue color, which comes from the presence of methane in its atmosphere. Neptune has a diameter almost four times that of Earth, making it the fourth-largest planet by diameter in our solar system. It has a very active atmosphere with high-speed winds and large storms, including the famous Great Dark Spot, which is a massive storm similar to Jupiter’s Great Red Spot, but it has since disappeared. Neptune also has a system of rings and at least 14 known moons, with the largest being Triton. Triton is particularly interesting because it is one of the coldest objects in the solar system, with a surface temperature of about -235 degrees Celsius (-391 degrees Fahrenheit). It is also unique among large moons in that it orbits Neptune in a direction opposite to that of Neptune’s rotation. Neptune has been visited by only one spacecraft, Voyager 2, which flew by the planet in 1989 and provided us with our best data and images of Neptune to date.