Scientists have explained why Neptune and Uranus are different colors despite having much in common.
The two planets farthest from the Sun are similar in mass, size, and atmospheric composition, but Neptune is clearly bluer than its neighbor.
A new study from Oxford University has suggested that the reason for this is due to a layer of fog on both planets.
Their appearances would be identical if it were not for this fog, said Professor Patrick Irwin, lead author.
Using observations from the Hubble Space Telescope, NASA’s infrared telescope facilities, and the Gemini North Telescope, researchers have developed a model to describe the layers of aerosols in the atmosphere of both planets.
The model includes three layers of fog at different heights.
In Uranus, the middle layer of fog is thicker than in Neptune, which affects the visible color.
Scientists also said that methane ice condenses in the middle layer of both planets, forming a rain of methane snow that drags fog particles deeper into the atmosphere.
Neptune has a more active, turbulent atmosphere, suggesting that it is more efficient at producing snow that removes more fog and keeps Neptune’s middle layer thinner.
Thus, Neptune appears bluer, while the excess fog in Uranus accumulates in the slow atmosphere and causes a lighter shadow.
The model also showed the presence of a second deeper layer.
Read more on Sky News: Plants grown on the lunar soil for the first time. The European mission to Mars could be on hold for years. A new type of stellar explosion has been discovered
When it gets dark, it causes dark spots on Neptune, such as the famous Dark Spot GDS-89.
Professor Irwin said: “This is the first model that simultaneously adjusts to observations of reflected sunlight from ultraviolet wavelengths to near infrared.”
Explaining the color difference between the planets was an “unexpected advantage” of the model, according to co-researcher Dr. Mike Wong of the University of California.