For decades, images taken of Neptune have looked like the planet has a deep blue hue, while Uranus seemed more green. However, these two ice giants may actually look more similar to eachother than astronomers previously believed. According to a study published January 5 in Monthly Notices of the Royal Astronomical Society, our solar system’s furthest planets’ true colors could both be similar pale shades of greenish blue.
[Related: The secret to Voyagers’ spectacular space odyssey.]
Images versus reality
NASA’s Voyager 2 mission remains the only flyby of both ice giants conducted by a spacecraft. It gave us the first detailed images of these far-flung planets. Voyager 2 conducted a flyby of Uranus in 1986, and the images revealed a planet with a more pale cyan or blue color. The vessel flew by Neptune in 1989 and the imagery showed a planet with a rich blue color.
However, astronomers have long understood that most modern images of both planets don’t accurately reflect their true colors. Voyager 2 captured images of each planet in separate colors and these single-color images were then put together to make composites. These composite images were not always accurately balanced, particularly for the planet Neptune which was believed to appear too blue. The contrast on the early Voyager images of Neptune were also strongly enhanced to better reveal the clouds and winds of the planet.
“Although the familiar Voyager 2 images of Uranus were published in a form closer to ‘true’ color, those of Neptune were, in fact, stretched and enhanced, and therefore made artificially too blue,” study co-author and University of Oxford astronomer Patrick Irwin said in a statement. “Even though the artificially-saturated color was known at the time amongst planetary scientists–and the images were released with captions explaining it–that distinction had become lost over time.”
Creating a more accurate view
In the new
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