--- title: Scientists Say Uranus Really Does Smell Like Rotten Eggs description: Scientists determined that clouds above the planet Uranus are made of the same gas that gives rotten eggs their distinctive, noxious smell canonical: https://time.com/5251988/uranus-hydrogen-sulfide-rotten-eggs-voyager/ author: Eli Meixler article:opinion: false article:content_tier: free article:published_time: 2018-04-24T04:23:51.000Z article:modified_time: 2026-02-23T20:03:56.658Z article:section: Science og:title: Scientists Say Uranus Really Does Smell Like Rotten Eggs og:description: Uranus' clouds are made up of the gas that gives rotten eggs their noxious smell og:url: https://time.com/5251988/uranus-hydrogen-sulfide-rotten-eggs-voyager/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt2356e65a0702fb57/69892e76db2987627925f74f/gettyimages-50579865.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 og:image:width: 1200 og:image:height: 675 og:image:alt: Uranus seen from its moon Miranda, (supe og:type: article twitter:card: summary_large_image twitter:title: Scientists Say Uranus Really Does Smell Like Rotten Eggs twitter:description: Uranus' clouds are made up of the gas that gives rotten eggs their noxious smell twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt2356e65a0702fb57/69892e76db2987627925f74f/gettyimages-50579865.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  # Scientists Say Uranus Really Does Smell Like Rotten Eggs. Here's Why by [Eli Meixler](https://time.com/author/eli/) ## Eli Meixler Apr 24, 2018 4:23 AM UTC  Uranus seen from its moon Miranda, as depicted by Voyager 2 spacecraft. Uranus seen from its moon Miranda, as depicted by Voyager 2 spacecraft.Time Life Pictures—The LIFE Picture Collection/Getty Images by [Eli Meixler](https://time.com/author/eli/) ## Eli Meixler Apr 24, 2018 4:23 AM UTC Scientists have determined that the atmosphere above the planet Uranus is full of a gas that makes the distant planet smell like rotten eggs. A new study, [published](https://www.nature.com/articles/s41550-018-0432-1) Monday in the journal _Nature Astronomy_, established the chemical composition of Uranus’ upper cloud deck for the first time. Using an instrument called the Near-Infrared Integral Field Spectrometer (NIFS) at the Gemini North telescope in Hawaii, researchers [determined](http://www.bbc.com/news/science-environment-43871497) that Uranus’ cloud cover is composed of hydrogen sulfide (H2S) gas, which is what gives rotten eggs their distinctive, noxious scent. “If an unfortunate human were ever to descend through Uranus’s clouds, they would be met with very unpleasant and odiferous conditions,” said study co-author Patrick Irwin of the University of Oxford, according to the BBC. Scientists had speculated that Uranus and Neptune’s clouds could also exhibit ammonia ice (NH₃), as on gas giants Jupiter and Saturn, but previous observations from both ground telescopes and the [Voyager 2 spacecraft](http://time.com/3173764/voyager-2-spacecraft-nasa/) were inconclusive. The new study [revealed](http://www.gemini.edu/node/21050) atmospheric differences between the gas and ice giants that could answer questions about the planets’ early history, scientists said. But future space travelers would succumb to Uranus’ hostile elements long before noticing the odor, according to Irwin. “Suffocation and exposure in the negative 200 degrees Celsius \[-392 Fahrenheit\] atmosphere… would take its toll long before the smell,” he said. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/5251988/uranus-hydrogen-sulfide-rotten-eggs-voyager/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/5251988/uranus-hydrogen-sulfide-rotten-eggs-voyager/"},"headline":"Scientists Say Uranus Really Does Smell Like Rotten Eggs. 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