Every planet in the solar system has its own unique appearance. Earth has azure oceans. Saturn has sparkling rings. And Neptune has fantastically bright clouds. However, for the first time in three decades, scientists have noticed that Neptune's clouds have almost disappeared, which has left them with many questions.
It is worth noting that the planet orbits at an average distance of 4.4 billion kilometers from the Sun and many believe that the Sun has something to do with this change.
Scientists are very interested in the planet and what happens there, but very little is known about Neptune at the moment. So far, only one spacecraft has visited it, Voyager 2, in August 1989. For this reason, astronomers rely on data from various telescopes.
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Neptune's clouds are a signature feature of the planet. Sometimes they're not as visible, but they do come back. However, a photo from 2019 showed that they had disappeared, except for a small section near the south pole.
“It was the first time we had seen anything like this,” Dutch astronomer Dr Imke de Pater, who works at the University of California, Berkeley, told the New York Times.
“There's nothing there. What's going on?“.
Expert Erandi Chavez and her colleagues published a study recently in the journal Icarus that documented cloud activity on Neptune between 1994 and 2022.
To solve the mystery, astronomers compared images of the planet from the Hubble as well as the Keck and Lick observatories with data on the Sun's cycles.
They concluded that the absence of clouds has some correlation with the 11-year solar cycle.
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The researchers found that clouds began to appear on Neptune about two years after the end of strong radiation .
The Sun's magnetic field reverses after some years, which is accompanied by an increase in UV radiation followed by a "quiet period".
The last cycle occurred in 2015 and then darkened in 2020, to the lowest level ever observed.
"These remarkable data give us the strongest evidence yet that Neptune's clouds are correlated with the Sun's cycle," said Dr de Pater.
“Our findings support the theory that the Sun's UV rays, when strong enough, may trigger a photochemical reaction that produces Neptune's clouds“.
Ms Chavez said: “Even four years later, the images we took showed that the clouds have not returned to previous levels.”
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“This is extremely exciting and unexpected, especially since Neptune's previous period of low cloud activity was not as dramatic and prolonged“.
Scientists are eagerly awaiting the next solar cycle to see if the planet change immediately afterward.
Source: www.news.com.au
