Rotten eggs, horse urine, formaldehyde, bitter almonds, alcohol, vinegar and a hint of sweet ether. That heady bouquet, according to Swiss researchers, is the "perfume" of comet 67P/Churyumov-Gerasimenko.

Scientists at the University of Bern said they have determined what the comet would smell like by analysing the chemicals in its coma, the fuzzy head surrounding the nucleus.

For this, they used one of the instruments aboard the European spacecraft Rosetta that is preparing to drop a lander onto the comet's icy surface on November 12.

Project leader Kathrin Altwegg, of the University of Bern, said the aroma will get stronger as 67P gets closer to the sun, causing it to release more gas and form the coma characteristic of comets.