Article by: Andacs Robert Eugen, on 01 June 2022, at 12:10 pm Los Angeles time

Astronomers have probably figured out a mystery about the two ice giants we have in our Solar System.

Uranus and Neptune seem quite similar at first glance and so it is. But have you ever wondered why Uranus has a lighter blue color than Neptune where a very dark blue is clearly visible?

Astronomers used three telescopes: the Hubble Space Telescope, the Gemini North Telescope, and the NASA Infrared Telescope Facility for the new scientific paper, published yesterday in the Journal of Geophysical Research.

Scientists have developed an atmospheric model for both planets, resulting in a large amount of fog on Uranus, while Neptune is in very small quantities.

"This is the first model to simultaneously fit observations of reflected sunlight from ultraviolet to near-infrared wavelengths," explained Irwin, who is the lead author of a paper presenting this result in the Journal of Geophysical Research: Planets. "It's also the first to explain the difference in visible colour between Uranus and Neptune."

The explanation is that while Uranus has a fairly stagnant atmosphere, Neptune has a turbulent atmosphere that creates more methane snow that removes fog.

Methane snow is found deep in the atmospheres of both planets, but due to the lazy atmosphere of Uranus, it cannot remove the formed fog, which makes the planet look a lighter blue.

"We hoped that developing this model would help us understand clouds and hazes in the ice giant atmospheres," commented Mike Wong, an astronomer at the University of California, Berkeley, and a member of the team behind this result. "Explaining the difference in colour between Uranus and Neptune was an unexpected bonus!"

Observations were made in ultraviolet, visible, and near-infrared wavelengths.