Amateur Astronomer Stumbles Upon Something Strange That Contradicts Previous Models of Jupiter's Atmospheric Composition

An amateur astronomer's innovative use of old traditional observation techniques has challenged long-held beliefs about Jupiter's cloud composition, revealing that the gas giant's iconic swirling clouds may not be made of frozen ammonia as previously thought, stated Space.com. Applying commercial telescopes with spectral filters available in any decent optical shop, a Colorado-based amateur astronomer, Steve Hill, identified the distribution of ammonia across Jupiter's atmosphere—a new line of investigation whose discoveries run somewhat contrary to those modeled on what makes up its cloudy atmosphere.
Citizen scientists change our view of Jupiter’s clouds. The collaborative effort between amateur and professional astronomers has led to a significant reevaluation of Jupiter's cloud composition. Previously thought to be composed of ammonia ice, new findings suggest that… pic.twitter.com/zHvU0KJJB4
— Nirmata (@En_formare) January 12, 2025
"I was astonished!" said Patrick Irwin of the University of Oxford, who first saw Hill's results. "At first, I was dubious that Steve's method could produce such detailed ammonia maps," according to Space.com. His skepticism quickly turned to excitement as patterns in Hill's data proved impossible to dismiss. Hill dusted off an old technique from the 1970s and 80s called band-depth analysis, in which he looked for specific wavelengths of light to get gas concentrations. He studied in some detail the composition of Jupiter's atmosphere by examining the absorption bands produced by methane at 619 nm and ammonia at 647 nm. The technique was all the more rewarding because the known properties of methane provided a reliable indicator of the levels of atmospheric pressure.

(Representative Image Source: Unsplash | Photo by NASA)
The findings challenged the basic assumptions of the atmosphere of Jupiter. As Irwin explained, "Astronomers will always assume a simple model unless there is overwhelming evidence that this simple model is flawed," stated Space.com. The observations showed that the reflected light came from cloud layers in which the conditions were too warm and the pressure too high for ammonia to freeze. Instead of ammonia ice, the research team proposed that Jupiter's clouds are probably made up of ammonium hydrosulfide and atmospheric smog created by photochemical reactions, according to Techno Science. These findings were further corroborated with more advanced telescopes, namely, the MUSE instrument on ESO's Very Large Telescope and even NASA's Juno Mission.
i saw rainbow parahelia in the afternoon- VERY excited to be racking up different ice cloud refraction phenomena :) and then the moon, venus, mars, and jupiter were all visible in the evening. beautiful final day of winter break ♡
— ヤヤ (@nerieae) January 11, 2025
As Hill noted in the original paper in Earth and Space Science, "Where ammonia is and is not provides a powerful tracer of weather processes on Jupiter, making it important for understanding the planet and others like it," as per Space.com. The same analytical techniques have been used to observe similar patterns in Saturn's atmosphere. The research showed that, in fact, only at those locations where strong updrafts occur can the pure ammonia ice clouds form; elsewhere, ammonia is destroyed by sunlight before it can rise high enough. This would then make for more complex cloud compositions, which helps explain the coloring and patterns visible on Jupiter's atmosphere.
It's a collaboration of amateur and professional astronomers that proves creative thinking about old technology pays off with major discoveries. More importantly, it shows that citizen scientists with modest equipment can still make significant contributions to our understanding of the solar system and open new possibilities for studying gas giants more effectively.