The combined efforts of amateur and professional astronomers have clarified the composition of Jupiter’s clouds, solving a long-standing mystery. It turned out that they did not consist of ammonia ice, as previously thought, but of ammonium hydrosulfide mixed with smog.
The results were published in the Journal of Geophysical Research: Planets. The discovery was made possible by amateur astronomer Dr. Steven Hill from Colorado. Using available telescopes and special filters, he showed that the ammonia and pressure in Jupiter’s upper cloud layers could be mapped. This confirms that the clouds are much deeper than previously thought, in a warm atmosphere where condensation of ammonia is impossible.
The study was led by Professor Patrick Irwin of the University of Oxford. His team applied Hill’s method to data obtained by the MUSE instrument on the Very Large Telescope (VLT) in Chile. MUSE uses spectroscopy to map ammonia and clouds in Jupiter’s atmosphere. Modeling of the interaction of light with gases and clouds confirmed that Jupiter’s main clouds are much deeper and composed of ammonium hydrosulfide.
Previously, such results were obtained by sophisticated methods available to only a few groups in the world. However, Hill’s method proved to be much simpler and more accessible. This confirmed that Jupiter’s main clouds are under much higher pressure than expected for ammonia ice.
“This simple method allowed us to see that Jupiter’s main clouds cannot be ammonia ice. The results prove that even amateurs can break new ground in studying Jupiter’s atmosphere,” said Prof. Irwin. Dr. Hill added that his goal was to demonstrate how a meaningful contribution to science could be made with affordable equipment.
This method allows amateurs to track changes in Jupiter’s atmosphere, particularly streaks, storms, and the Great Red Spot. According to John Rogers of the British Astronomical Association, this helps link weather changes on the planet to fluctuations in ammonia.
Photochemical processes active in Jupiter’s atmosphere explain why ammonia does not form thick clouds. Ammonia mixes with photochemicals to form ammonium hydrosulfide, which gives clouds their characteristic red and brown hues. In regions with intense convection, ammonia ice clouds can form, which have been observed by spacecraft, particularly Galileo and Juno.
The method has also been applied to the study of Saturn. The results showed that the main clouds there are below the ammonia condensation level, indicating similar photochemical processes.
This discovery confirms that collaborations between amateur and professional astronomers can greatly expand our understanding of the dynamics of the atmospheres of gas giants.
Earlier we reported on how Jupiter was found to have a surprising resemblance to Earth.
According to Phys.org
