stsci_2023-019a August 17th, 2023
Credit: NASA, ESA, Erandi Chavez (UC Berkeley), Imke de Pater (UC Berkeley)
This sequence of Hubble Space Telescope images chronicles the waxing and waning of the amount of cloud cover on Neptune. This long set of observations shows that the number of clouds grows increasingly following a peak in the solar cycle – where the Sun’s level of activity rhythmically rises and falls over an 11-year period.
The theory is that the increased ultraviolet radiation from the Sun, during its peak of activity, causes chemical changes deep in Neptune’s atmosphere. After a couple years this eventually percolates into the upper atmosphere to form clouds.
In 1989, NASA’s Voyager 2 spacecraft provided the first close-up images of linear, bright clouds, reminiscent of cirrus clouds on Earth, seen high in Neptune’s atmosphere. They form above most of the methane in Neptune’s atmosphere and consequently are not blue, but reflect all colors of sunlight. Hubble picks up where the brief Voyager flyby left off by continually keeping an eye on the planet yearly.
Provider: Space Telescope Science Institute
Image Source: https://hubblesite.org/contents/news-releases/2023/news-2023-019
Curator: STScI, Baltimore, MD, USA
Image Use Policy: http://stsci.edu/copyright/
Detailed color mapping information coming soon...
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