Neptune Turned Out To Be Not As Blue As Thought
Neptune’s true color is a pale greenish blue, similar to the color of Uranus, in contrast to popular images that show it to be a much deeper shade of blue.
NASA’s Voyager 2 spacecraft flew past the outer planets in the 1980s and sent back photographs showing that Uranus and Neptune had noticeably different colors.
The true colors of Neptune and Uranus have been revealed in a new study using data from the Hubble Space Telescope and the Very Large Telescope of the European Southern Observatory in Chile. Using spectrometers on these telescopes, scientists obtained data to build a refined digital model to analyze Voyager 2’s raw data. As a result, Neptune turned out to be almost the same color as Uranus – aquamarine, not azure. Neptune turned out to be slightly darker because the haze in its upper layers was slightly thinner than on Uranus and reflected less sunlight.
The new study also solved the mystery of Uranus’ color change over time. During its year, which lasts 84 Earth years, Uranus turns toward the Sun either with its equator or its pole (it lies on its side in relation to the ecliptic). In the polar regions, Uranus’ atmosphere contains more methane, which absorbs red wavelengths. Therefore, when turning its pole towards the Sun, the planet acquires a greenish tint, which was also confirmed in a new scientific work.
