Apr 24, 2018

Rotten egg gas around planet Uranus

The planet Uranus has clouds made up of hydrogen sulphide, the gas that gives rotten eggs their unpleasant smell.

The possibility of this gas being present in the atmosphere of the seventh planet had long been debated, but has now been confirmed for the first time by observations at a telescope on Hawaii.

The malodorous gas was detected high above the giant planet's cloud tops.

The findings could shed important new light on how the outer planets formed.

A team of researchers have published their results in the journal Nature Astronomy.

Despite previous observations by ground telescopes and the Voyager 2 spacecraft, the composition of Uranus' atmosphere had remained unclear.

Scientists have long wondered whether hydrogen sulphide (H₂S) or ammonia (NH₃) dominate the ice giant's cloud deck, but have lacked definitive evidence either way.

The data were obtained with the Near-Infrared Integral Field Spectrometer (NIFS) instrument on the Gemini North telescope on Hawaii's Mauna Kea summit.

The spectroscopic measurements break infrared light from Uranus into its component wavelengths. Bands in the resulting spectrum known as absorption lines, where the gas absorbs infrared light coming from the Sun, allowed the scientists to "fingerprint" components of Uranus' atmosphere.

"Now, thanks to improved hydrogen sulphide absorption-line data and the wonderful Gemini spectra, we have the fingerprint which caught the culprit," said co-author Patrick Irwin, from the University of Oxford.

(BBC News)