Neptune is the eighth planet in our Solar System. It is now technically the last planet in our Solar System and the furthest from the sun. Pluto is no longer classed as a planet. Neptune was named for the Roman god of the sea and has a striking deep-blue color. But why is Neptune blue?
Neptune was only officially discovered in 1846 by mathematical prediction. This is because it is not visible without high-powered telescopes. In 1989 NASA’s Voyager 2 recorded real detailed observations of the planet, including its color. Neptune, along with Uranus, Jupiter and Saturn, is a gas giant planet. It is the densest giant planet.
Neptune is the third biggest planet in our Solar System. It has the fourth largest diameter and is roughly 17 times the mass of the Earth. It is also one of the coldest planets due to its distance from the sun.
The reason for Neptune’s blue color is due to its atmosphere’s chemical makeup. Neptune’s atmosphere is mainly comprised of liquid ammonia, hydrogen, helium and methane. Methane is concentrated in the upper portion of Neptune’s atmosphere. The heavy methane clouds absorb the light from the sun. The red light wavelengths are absorbed more easily. The blue light wavelengths, which are shorter, are reflected back into space. Therefore we see the blue light and not the red, making Neptune appear a deep blue to us.
If you were to get closer to Neptune you would notice variations in its color. This is because of the way the clouds are formed above the surface. Neptune experiences a lot of storms with winds often surpassing 2.400 km/hour. Indeed, Neptune’s storms are the fastest in the Solar System. This contributes to the shifts in cloud cover.
Neptune vs. uranus
Uranus is also blue in color although more of a blue-green than Neptune’s deep blue. The fact that Uranus and Neptune differ in their shades of blue means that the chromophores found in their respective atmospheres are slightly different. Chromophores are chemicals that influence color. Scientists, however, have not yet determined which additional chromophore is influencing the color of Neptune’s atmosphere.