New Images Reveal What Neptune Really Looks Like

The color is not at all like in school textbooks.

For a long time, the most vivid images of Neptune and Uranus were taken by "Voyager 2," which flew by in the late 1980s. Its photos always raised one question: why did these two planets, which are very similar in many ways, have such different colors?

Uranus, judging by the probe's images, had a beautiful sea wave color and resembled a duck egg. Neptune, on the other hand, was noticeably darker, a shade of blue. Considering that the atmospheric compositions of the planets are practically identical, the difference in their appearance seemed striking. This became a real mystery for scientists.

However, researchers have now reprocessed the data from "Voyager 2" and discovered that they were deeply flawed from the very beginning. Uranus and Neptune are actually very close in hue.

The reason for the error is that the images were taken in different dynamic ranges. Additionally, the images of Neptune were processed in a way that emphasized contrast and deepened its true color, making it appear bluer than it actually is. This is discussed in a scientific paper by planetary physicist Patrick Irwin from Oxford.

Now, Oxford scientists have managed to determine the true color of Neptune, the most distant planet in the Solar System. They used the Space Telescope Imaging Spectrograph (STIS) and the multi-object spectroscopic investigator of the Very Large Telescope.

The scientists utilized data from each telescope to independently determine the true color of Neptune and Uranus, and then applied this information to reprocess the images from "Voyager 2." The result was predictable: Neptune is much lighter than previously thought, and its color is very similar to Uranus. The main difference is that Neptune is slightly bluer, likely due to a thinner layer of atmospheric haze.

New observations also solved another mystery - why Uranus slightly changes color throughout its year, which lasts 84 Earth years. During the solstice, when one of the poles is facing the Sun, the planet appears a bit greener. And during the equinox, when the equator is facing the Sun, Uranus becomes slightly bluer.

This is related to the planet's unusual orientation. It is tilted in such a way that its axis of rotation is perpendicular to the plane of the Solar System's orbit. As a result, there is much less methane at the poles than at the equator, which alters how the planet reflects sunlight, as methane absorbs red wavelengths.