It’s a color loved by interior designers, but duck egg blue also seems to be splashed across our solar system, with research suggesting it’s the true color of both Uranus and Neptune.
The new work puts to rest the common belief that Neptune has a deep blue color, suggesting that both planets have a similar color – with Neptune only slightly bluer than Uranus.
“Uranus still looks dull and quite boring, but Neptune also looks quite washed out when you do the full true color reconstruction,” said Prof Patrick Irwin, first author of the study at the University of Oxford.
The color of the ice giants this has long been known to be the result of high levels of methane in their atmosphere, a gas that absorbs green and red light. Research by Irwin and colleagues had previously suggested that Neptune was the slightly bluer of the two planets because one of the layers of aerosol in its atmosphere was more transparent.
However, images compiled from data collected by Nasa’s Voyager 2 spacecraft during flybys in the 1980s led to a misconception about the planets’ true colors, with Neptune depicted as deep blue because images of it were contrast-enhanced to emphasize his duller features.
“Although these images were released including captions saying they were ‘enhanced’ or ‘stretched,’ these captions inevitably became separated from the images over time and gave rise to the long-standing and persistent misunderstanding of the relative colors of these two planets .write the researchers.
The team’s new true-color images of the planets show that both have a pale blue-green color, with very similar results obtained even when comparing data from different instruments on the Hubble Space Telescope or data from the Voyager missions.
The research also shed light on the mystery of why Uranus appears to change color with its seasons. Observations have previously revealed that the planet appears to be greener during its summer and winter when its polar regions face Earth and the Sun.
Using computer models, the team suggests that this is not only due to the polar regions of Uranus having lower levels of methane, but also because a haze of frozen methane particles forms over the sun-facing pole, which scatters light and therefore increases the reflection of green. and red wavelengths.
But Irwin said questions remain, including why methane levels were lower over the poles of Uranus, and why such a haze would form over the warmer pole.
“There is a lot about these planets that we simply don’t understand,” he said, adding that to learn more, Nasa and the European Space Agency (ESA) had to join forces and send a spacecraft to them.
“We have to actually go into orbit and drop a probe so we can see exactly what’s there, rather than trying to piece it together from remote observations,” he said.