What Does A Comet Smell Like?

Mix the aroma of rotten eggs with a whiff of horse stables, throw in a hint of ammonia and formaldehyde, and you've got eau de Comet 67P/Churyumov-Gerasimenko.
Scientists at the University of Bern in Switzerland discovered the comet's pungent scent by analyzing a mixture of molecules detected in the comet's coma, the cloud of particles and gases around the space rock's nucleus.