Neptune’s Clouds Disappeared Based on 30-Year Data, Correlates With Solar Cycle

Scientists noticed that the clouds in Neptune had disappeared. According to them, the phenomenon was related to the sun's ongoing cycle.

Neptune's Clouds Disappeared

On Thursday, astronomers made an unexpected update regarding Neptune, one of the ice giants in our solar system. The clouds of the azure world have almost completely vanished.

The researchers found an odd trend starting in 2019 after studying photos of the globe acquired between 1994 and 2022. Cloud cover appeared to be thinning across the planet's middle latitudes. Eventually, all traces of the clouds were gone.

Imke de Pater, an emeritus professor of astronomy at the University of California, Berkeley and the senior author of a research on the results, stated in a press release that she was startled by how swiftly clouds evaporated on Neptune. Within a few months, the cloud activity essentially dropped.

De Pater and his other researchers were intrigued by this finding and decided to investigate more. They did come up with a rather intriguing explanation. The team hypothesizes that the behavior of our sun's 11-year activity cycle and Neptune's clouds are intimately intertwined.

According to the team's Neptune analysis, the sun generates a lot of UV radiation as its magnetic fields change during the solar cycle. Given how extensive the sun is, the researchers say that radiation "floods" the rest of the solar system.

Naturally, it's simple to think that this circumstance could impact one or more planets, including Neptune, despite the fact that it is a far-off, windy planet located approximately 2.8 billion miles (4.5 billion kilometers) from our solar.

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Neptune's Clouds, Solar Cycle's Correlation

The scientists compiled 30 years of beautiful photographs of Neptune acquired by powerful observatories, including NASA's Hubble Space Telescope and W. M. Keck Observatory in Hawaii, to analyze where the planet's clouds had vanished. They discovered that there appeared to be a direct association between the number of clouds on Neptune and the stage that our sun's solar cycle was in.

Neptune showed some good cloud covering about two years after the cycle's apex, often known as the primary event of magnetic field flipping. The clouds above the planet's atmosphere of hydrogen, helium, and methane disappeared after that peak. Neptune appears so intensely blue because of its methane concentration.

It suggests that Neptune's hazy cap may have been created by a photochemical reaction initiated by the sun's UV radiation, which is highest during solar peak. She said that response might take around two years to kick in. This would explain why the researchers saw many Neptunian clouds two years after the solar peak.

According to de Pater, these extraordinary findings provide the clearest proof that Neptune's cloud cover is correlated with the sun's cycle.

The scientists also observed that the brightness of this frozen blue planet appeared to increase with the number of clouds present since more sunlight was reflected off of them.

Although possible relationships between variations in Neptune's brightness and the cycle of solar activity have been investigated, no one cause has been found so far, according to the study's authors. Secular variations in brightness must have a different origin from seasonal influences, even though they are likely crucial for slow, progressive changes.