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- Uranus is an ice giant planet in the outer solar system,<\/strong> similar to Neptune. It has a deep atmosphere of hydrogen, helium and methane.<\/li>\n
- NASA\u2019s Hubble Space Telescope observed Uranus over 20 years for a detailed study.<\/strong> The observations provided new insights into the mysterious planet\u2019s atmosphere.<\/li>\n
- Hubble studied the distribution of methane and aerosol clouds over time,<\/strong> which varied depending on the seasons and the latitudes of the methane and clouds.<\/li>\n<\/ul>\n
Hubble reveals weird Uranus in new 20-year study<\/h3>\n
NASA\u2019s Hubble Space Telescope observed the distant ice giant planet Uranus repeatedly over the course of 20 years. The Space Telescope Science Institute (STScI) said on March 31, 2025, that the two-decade long study has yielded new insights into the dynamics of its deep hydrogen, helium and methane atmosphere. The findings can also help astronomers better understand exoplanets that are similar in size and composition to Uranus.<\/p>\n
2025 EarthSky lunar calendar is available now. A unique and beautiful poster-sized calendar with phases of the moon for every night of the year. Get yours today!<\/p>\n
20 years of Uranus observations<\/h3>\n
Hubble observed Uranus four times during the 20-year period, in 2002, 2012, 2015 and 2022. Erich Karkoschka at the University of Arizona and Larry Sromovsky and Pat Fry at the University of Wisconsin led the research team. They used the Space Telescope Imaging Spectrograph (STIS) instrument on Hubble to chronicle seasonal changes in Uranus\u2019 bluish-green atmosphere.<\/p>\n
Why did it take so long? Uranus has the most extreme seasons of any planet in the solar system. This is due to its axial tilt of a whopping 98 degrees. Each of its four seasons lasts 21 years, and a year on Uranus is just over 84 Earth years!<\/p>\n
Uranus\u2019 atmosphere is much deeper than Earth\u2019s and consists mostly of hydrogen and helium, plus some methane. There are also trace amounts of water and ammonia.<\/p>\n
The 20-year study revealed that methane is not evenly distributed through Uranus\u2019 atmosphere. This is different than what happens on the gas giant planets Jupiter and Saturn. Notably, on Uranus, the methane is strongly depleted near the planet\u2019s poles. The depletion remained pretty much unchanged over the 20 years. Interestingly, however, aerosols and hazes did change. They brightened in the north polar region. This is happening as the planet starts to approach its northern summer solstice in 2030.<\/p>\n
![\"Sky-blue](\"https:\/\/earthsky.org\/upl\/2023\/10\/Uranus-Webb-NASA-ESA-CSA-STScI-J-DePasquale-STScI.png\")
View larger. | NASA\u2019s James Webb Space Telescope captured this stunning view of Uranus and its rings on February 6, 2023. Image via NASA\/ ESA\/ CSA\/ STScI\/ J. DePasquale (STScI).<\/figcaption><\/figure>\n \n
? By repeatedly training Hubble on Uranus over 20 years, astronomers have gained new understanding of the ice world\u2019s complex atmosphere: bit.ly\/4hVo8ih ? ?<\/p>\n
\u2014 spacetelescope.bsky.social (@spacetelescope.bsky.social) 2025-03-31T17:04:54.678Z<\/p>\n<\/blockquote>\n
Analyzing the images<\/h3>\n
The composite of 16 images included above shows the observations of Uranus\u2019 atmosphere in both visible and near-infrared light. It also shows the aerosols, hazes and methane depletion in the atmosphere. Over the 20 years, the south polar region started going into the shadow of winter. Conversely, the north polar region came into sunlight as summer approached.<\/p>\n
In the top row, we see Uranus as it looks to the human eye, in visible light. It\u2019s bland, with only subtle variations. The second row shows Uranus in false color, from both visible light and near-infrared light observations. The colors depict varying amounts of methane and aerosols in the atmosphere. Green areas generally indicate less methane than blue areas, and red areas are where there is no methane.<\/p>\n
The third row shows bright areas on Uranus, with more aerosol clouds and haze in the atmosphere. By contrast, the darker areas have less clouds. Finally, the fourth row focuses on methane. Bright areas have less methane and dark areas have more methane.<\/p>\n
Both the third and fourth row images are based on 1,000 different wavelengths (colors), ranging from visible to near infrared light.<\/p>\n
The aerosols and methane behave differently at different latitudes. Neither of them showed much change over the 20 years at middle and low latitudes. But near the north pole, the aerosols significantly increased. The methane depletion, however, remained high at both poles.<\/p>\n
Astronomers can also now use the findings to help better understand exoplanets that are similar in size and composition to Uranus.<\/p>\n
![\"Man](\"https:\/\/earthsky.org\/upl\/2025\/04\/Erich-Karkoschka-University-of-Arizona-LPL-May-25-2016.jpg\")
Erich Karkoschka at the University of Arizona is one of the lead researchers of the Uranus study. Image via Lunar and Planetary Laboratory.<\/figcaption><\/figure>\n Uranus is weird<\/h3>\n
The first \u2013 and still only \u2013 spacecraft to visit Uranus was Voyager 2 on January 24, 1986. It saw Uranus up close for the first time ever. While Uranus\u2019 atmosphere was a lovely bluish-green, it was also bland, not like the turbulent, striped atmospheres of Jupiter and Saturn. But one of the weirdest things about Uranus is that it rotates sideways. Its axis is extremely tipped, at about 98 degrees. By comparison, Earth\u2019s axis only tips 23.45 degrees.<\/p>\n
Another study in late 2024 also suggested that both Uranus and Neptune might have deep oceans of water beneath their atmospheres. This could also explain why both planets have unusually disorganized magnetic fields.<\/p>\n
Bottom line: The Hubble Space Telescope\u2019s 20-year study of Uranus has yielded new insights about the enigmatic ice giant\u2019s atmosphere and how it might compare to exoplanets.<\/p>\n
Via Hubblesite<\/p>\n
Read more: Are Uranus and Neptune hiding oceans of water?<\/p>\n
Read more: New Uranus image from Webb shows rings, polar cap<\/p>\n
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\n - NASA\u2019s Hubble Space Telescope observed Uranus over 20 years for a detailed study.<\/strong> The observations provided new insights into the mysterious planet\u2019s atmosphere.<\/li>\n