Why Neptune and Uranus have different colors?

New telescope and space observations have revealed the cause behind this color difference. Neptune and Uranus have similar sizes, masses, and atmospheric conditions.

 Neptune and Uranus are roughly the same blue color.

After NASA's Voyager 2 spacecraft passed by these two planets in the 1980s, scientists discovered that Neptune has a bright blue appearance. Meanwhile, Uranus has a lighter green color.

The astronomers used the Gemini Telescope and NASA's Infrared Telescope Facility, both in Hawaii and the Hubble Space Telescope, to create a model that would match those of Neptune's observations. and Heavenly King.

Scientists have determined that there is an accumulation of haze in the atmosphere of Uranus. This layer of haze is thicker on Uranus than on Neptune. This is what causes Uranus to be lighter in color.

Without this haze in the atmospheres of both planets, astronomers believe that Neptune and Uranus would have a nearly identical blue color. The study was published in the journal Geophysical Research: Planets.

Previously, to understand this difference, scientists often focused on the upper part of the planet's atmosphere at specific wavelengths of light.

Lead author of the new study - Patrick Irwin, Professor of Planetary Physics at the University of Oxford (UK), said: 'This is the first model that is consistent with the observation of sunlight reflected from wavelengths. ultraviolet to near infrared.

This is also the first finding that explains the visible color difference between Uranus and Neptune'.

The model also probes deeper layers of the atmosphere including fog particles, in addition to methane clouds and hydrogen sulfide ice. The team analyzed three layers of aerosols at different heights above Uranus and Neptune. The middle layer of the fog particles is the factor that affects the color the most.

On both planets, the middle layer is where the methane ice turns into methane snow. Neptune has a more active turbulent atmosphere than that of Uranus. So methane and snow particles prevent haze from forming on Neptune.

The scientists believe this model could also help explain why dark spots appear on Neptune, but are less common on Uranus. The team says it's most likely due to the darkening of the deepest layer of the atmosphere. This layer is more visible on Neptune.