The Rosetta comet smells a bouquet of odours: like rotten eggs, horse pee, alcohol and bitter almonds, European scientists said. An instrument aboard the probe Rosetta has detected some intriguing chemical signatures from Comet 67P/Churyumov-Gerasimenko since their rendezvous in deep space in August, they said. “If you could smell the comet, you probably wish that you hadn’t,” the team said wryly in a blog posted on the European Space Agency (ESA) website. “The perfume of 67P/C-G is quite strong, with the odour of rotten eggs (hydrogen sulphide), horse stable (ammonia) and the pungent, suffocating odour of formaldehyde,” said Kathrin Altwegg, Rosina’s chief scientist.
The research team used the two mass spectrometers in Rosetta’s ROSINA instrument to determine what the comet would smell like. The spectrometers allowed the team to see the chemistry in the gas cloud, or coma, around the comet’s nucleus. In Churumov-Gerasimenko’s defense, most comets probably have a similar smell, said Carey Lisse, a scientist at Johns Hopkins University, who was not involved in the research. “In general, you don’t want to breathe in comets,” he said.
“This is mixed with the faint, bitter, almond-like aroma of hydrogen cyanide. Add some whiff of alcohol (methanol) to this mixutre, paired with the vinegar-like aroma of sulphur dioxide and a hint of the sweet aromatic scent of carbon disulphide, and you arrive at the ‘perfume’ of our comet.” The detection of so many different molecules at this stage has been a surprise, ESA said. The Rosina team believed only the most volatile molecules – carbon dioxide and carbon monoxide – would be released as the comet’s icy surface started slowly to warm.”They are mostly water, but they also have a lot of primitive organics that might smell like the La Brea tar pits.”
The researchers at Bern said they were surprised to find so many different types of molecular materials in the comet’s coma, especially because it is still three times the distance from the sun as the Earth. They expect that as the comet moves closer to the sun, more gases will be released, and the comet will smell even worse.