An anonymous reader writes: According to a study published in Nature Astronomy, scientists have determined that the atmosphere of Uranus smells like rotten eggs. The smell of Uranus was determined by the use of an Near-Infrared Integral Field Spectrometer (NIFS), an instrument that allows scientists to determine what an atmosphere is composed of based upon the reflections of sunlight that bounce off of it. Specifically, the clouds in Uranus' upper atmosphere consist of hydrogen sulfide, the molecule that makes rotten eggs so stinky. "If an unfortunate human were ever to descend through Uranus' clouds, they would be met with very unpleasant and odiferous conditions," study lead author Patrick Irwin, of Oxford University in England, said in a statement. But that wayward pioneer would have bigger problems, he added: "Suffocation and exposure in the negative 200 degrees Celsius [minus 328 degrees Fahrenheit] atmosphere, made of mostly hydrogen, helium, and methane, would take its toll long before the smell."