Uranus and Neptune they have many characteristics in common: similar mass, size and atmospheric composition. However, it looks remarkably different: in the visible wavelength, Neptune appears deeper blue than Uranus..
Using observations from the Hubble Space Telescope, NASA’s Infrared Telescope, and the Gemini North Telescope, researchers have developed a unique atmospheric model which combines the observations of the two planets.
The model reveals that the excess of haze over uranus accumulates in the static atmosphere of the planet, making it appear that the planet is one shade lighter than Neptune. The model also reveals the presence ofand a second deeper layerthat when it gets dark, would explain the dark spots in their atmospheres, such as the famous Great Dark Spot (GDS) observed by Voyager 2 in 1989.
Differences between Uranus and Neptune
new investigations they suggest that the layer of mist concentrate that exists on both planets it is thicker on Uranus than on Neptune, and “brightens” the surface of Uranus more than that of Neptune. If this haze didn’t exist on Neptune and Uranus, the two would look almost identically blue.
This conclusion is drawn from a model that the international group of researchers, led by professor of planetary physics Patrick Irwin, of the University of Oxford, developed to describe the aerosol layers in the atmospheres of Neptune and Uranus.
Previous research into the upper atmospheric layers of these planets had focused on what the atmosphere looked like at only certain wavelengths. However, This new model combines observations of the two planets in a wide range of wavelengths, simultaneously.
The new model also includes fog particles in deeper layerswhere previously thought to exist only methane and hydrogen sulfide ice clouds.
The Aerosol-2 layer, the key to the color difference between Uranus and Neptune?
The model developed by the group consists of three layers of aerosols at different altitudes. The key layer affecting colors planets is interlayerwhich is a layer of haze particles —called the Aerosol-2 layer— which is thicker on Uranus than on Neptune.
The group suspects that on both planets, methane ice condenses on particles in this layerdragging them into the atmosphere in a bath of methane snow.
Given that Neptune has a more active and turbulent atmosphere than Uranus.the group thinks the atmosphere of Neptune is more effective at mixing methane particles into the haze layer and producing snow. This process would remove more haze and keep Neptune’s layer thinner.
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