It turns out that the comet the Rosetta mission has been chasing for the last decade is a stinker. Literally.
Researchers from the University of Bern in Switzerland say that if you could take a whiff of the cloud of gas surrounding the icy nucleus of comet 67P/Churyumov-Gerasimenko you would smell a pungent mix of hydrogen sulfide (rotten eggs); ammonia (horse stable); and formaldehyde.
There would also be a hint of the smell when a match is struck (sulfur dioxide) and a whiff of alcohol (methanol). Carbon disulfide would add just a touch of sweetness, the scientists say.
In all -- eau du Churyumov-Gerasimenko would be pretty unpleasant.
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.
"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.