Neptune's clouds disappear, the main suspect is the Sun

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Three decades of observations of Neptune managed to link the disappearance of its clouds with solar cycles. The periodic increase in the Sun's activity affects the last main planet in the solar system, although it is 4.5 billion kilometers from the star. The analysis was possible with monitoring sequences carried out by NASA's Hubble Space Telescope.

Neptune receives approximately 0.1% of the sunlight that Earth receives. It bel Phone Number List ongs to the category of ice giant planets and its atmosphere is mainly composed of hydrogen, helium and methane. It is also a gaseous body like Jupiter and Saturn , so scientists can only see nebular formations covering the planet.

Since the Voyager 2 spacecraft provided the best photos of Neptune's surface in 1989, astronomers have known that the planet has a cover of bright clouds distributed at the poles. 30 years later, thanks to Hubble monitoring, scientists realized that the blue planet had lost its clouds. By 2020, Neptune was just an undisturbed body in space.

Neptune is running out of clouds in less than 30 years.
Neptune is running out of clouds in less than 30 years. /NASA
The change in Neptune's clouds was not related to the planet's seasons. The formations in the atmosphere disappeared in less than three decades, while the seasonal changes of the star occur every 40 years.

A team of researchers from the University of Barkeley found a possible explanation for the atmospheric change. The formation of Neptune's clouds and their dispersion coincided with the beginning and end of solar cycles.

The solar cycle is the period in which the Sun's magnetic field changes and reverses its polarity . The phenomenon occurs every 11 years without interruption. As the period comes to an end, solar flare activity increases and sunspots appear throughout the star's corona . There is a peak of solar activity, then the star reverses polarity and begins a decade-long calm.



The sun's cycles are linked to Neptune.
Peaks in solar activity coincide with the appearance of clouds. SPACE TELESCOPE SCIENCE INSTITUTE OFFICE OF PUBLIC OUTREACH
The researchers were able to establish a direct link with ultraviolet radiation from the Sun and the Neptunian atmosphere. Specifically, two years after each peak of the solar cycle, clouds appeared on the planet's surface. An increase in reflectivity was also found that coincided with the presence of clouds. Neptune shined brightly in 2002, dimmed in 2007, reflected again in 2015, and went out in 2020, just as its clouds disappeared.

"Our findings support the theory that the Sun's UV rays, when strong enough, can trigger a photochemical reaction that produces Neptune's clouds," explained Imke de Pater , professor in the Barkeley Department of Astronomy and co-author of the research. .

Research into Neptune's climate will continue in the coming years. In addition to understanding how the frozen giant of the solar system works, it will also help to understand future exoplanets that have the same characteristics as it.