There has been a lot of talk about this in the last few weeks Uranus thanks to new images from the James Webb Space Telescope. The external gas giants will not be visited by robotic missions for some time and the first attempt could be made by China thanks to the Tianwen-4 mission, which could be launched in 2029 and is expected to arrive in 2045. A new study by a team ofUniversity of Oxford However, he tried to clarify an interesting point Uranus And Neptune.
Uranus captured by HST. Click on the image to enlarge it
Thanks to the images taken by Voyager 2 (but not only), we know that these two gas giants have a different color, with the first tending towards light cyan and the second towards bluish blue. Thanks to a new processing model, although they would be very different from Jupiter and Saturn, they would be much more similar to each other than one would expect.
The true colors of Uranus and Neptune in a new study
He was the one who talked about it Patrick Irwin (from Oxford University) in the monthly announcement the Royal Astronomical Society. The team he led figured out how Uranus And Neptune actually have one Color associateable with greenish blue. The initial error would be due to the imaging system typically used on space missions, including Voyager 2.
The initial images are monochromatic and are then colored to achieve the most realistic appearance possible (at least that’s what we try to do). However, the balance of the various components would not have been precise and NeptuneIn particular, it would have turned out bluer than it actually is.
Even increasing the contrast to improve some details, such as the clouds in the atmosphere, would have resulted in a change in coloring. The professor Irwin stated that “Although the images of Uranus known from Voyager 2 were released in a form closer to the true color, those of Neptune were actually stretched and enhanced, thus artificially rendered blue. Although the artificially saturated color was well known among planetary scientists at the time – and the images were published with captions explaining this – this distinction had been lost to time.”.
The team then applied a new model to the original data collected by Voyager 2 and Hubble’s Wide Field Camera 3 to reconstruct a coloring more accurate than Neptune And Uranus. The model is based on data obtained with the Hubble Space Telescope’s Space Telescope Imaging Spectrograph and the Very Large Telescope’s Multi Unit Spectroscopic Explorer instrument.
Animation showing the changing of the seasons on Uranus
As further additional information, the same study puts forward a hypothesis as to why Uranus It changes color slightly during its 84-year orbit around the Sun. During the solstice, when one of the poles faces the sun, the gas giant’s color appears slightly greener, and during the equinox it appears slightly bluer. The light that comes from the star and hits the poles has the greatest influence on the color and overall brightness of the planet.
The reason would be a higher reflectivity in the green and red wavelength range (compared to the blue), since methane is less abundant at the poles than at the equator. Besides, there would be something like that frozen haze (observed in summer) consists of frozen methane that gradually thickens as the equinox passes to the solstice.