Comets stink, and not just because they have the potential to cause cataclysmic devastation if they ever came hurtling through our atmosphere and made impact with Earth. These "cosmic snowballs of frozen gases, rock, and dust roughly the size of a small town" (as described by NASA) literally stink to high heaven, according to scientists at Switzerland's University of Bern. One comet does, anyway: Researchers analyzed the "perfume" of comet 67P/Churyumov-Gerasimenko and said that its BO is apparently a combo of "rotten eggs, horse urine, formaldehyde, bitter almonds, alcohol, vinegar, and a hint of sweet ether," the AP reports. "If you could smell the comet, you would probably wish that you hadn't," reads a blog post on the European Space Agency site.
The scientists were able to surmise what the comet would smell like by examining the gas emitted by the "coma," the comet's head, Phys.org reports. Luckily, instead of a squeamish human, a mass spectrometer aboard the space probe Rosetta was assigned the task of parsing out the perfumed molecules of 67P, including ammonia, methane, hydrogen sulfide, hydrogen cyanide, and "the pungent, suffocating (odor) of formaldehyde," notes the ESA post. The probe caught up to the comet in August after chasing it nearly 4 billion miles; it will be sending its Philae robot lander onto the comet proper on Nov. 12, NASA reports. And it appears the comet's odoriferous odyssey is just beginning: The lead scientist on the project says that as 67P gets closer to the sun, it will start stinking up the cosmos even more. (Whatever happened to NASA's plans to harpoon comets?)