Colin Snodgrass is unwrapping a series of nested plastic bags with the care you would normally reserve for bomb disposal. With the first layer off, I already understand why, as a sharp, unpleasant scent invades my nostrils.
I’m getting my first whiff of eau de comète, a perfume crafted to mimic the aroma of 67P/Churyumov–Gerasimenko as sniffed by the European Space Agency’s Philae lander, which touched down on the comet’s surface in 2014. It really is like nothing I’ve ever smelled.
The dense pong was created by scent firm The Aroma Company at the request of Snodgrass, a researcher at the Open University in Milton Keynes, UK, and other members of the Rosetta mission team. They will be handing out samples at theRoyal Society summer exhibition in London next month. “We have a bunch of postcards impregnated with this,” he says.
As Snodgrass removes the second bag, I almost feel the smell as a physical presence inside my skull, and yet there are two more bags to go. I ask if he has become desensitised. “A little, yes,” he says with a grin.
When Philae landed on 67P, its sensors picked up the presence of hydrogen sulphide, ammonia and hydrogen cyanide in the comet’s coma – gases which smell of rotten eggs, cat urine and bitter almonds.
“It’s not that bad”
The smell before me isn’t directly derived from these noxious compounds – good thing, given that some are poisonous – but the company created a scent that should reflect the whiff of 67P. “Most of the coma is water vapour, carbon dioxide and carbon monoxide, and they don’t smell of anything,” says Snodgrass. “We’ve picked the things that are the smelliest.”
As he opens up the final bag, the full heft of 67P’s bouquet hits me in the face. Surprisingly, it’s not actually as foul as my first impression led me to believe – somehow a few floral notes are now coming through. “I find it similar to lily,” says Geraint Jones of University College London, who took delivery of the samples at home, much to the chagrin of his wife. “It’s not that bad,” says Snodgrass.
Thankfully, the sample the pair have today is far more concentrated than those they will be inflicting on the public. If you can’t get to the Royal Society to smell it yourself, the team has bought enough postcards for future outreach events, so you may get another chance.
But can we really transmit a smell from a comet half way across the Milky Way? “If you could smell a comet, this is what you would get, but it would be difficult to actually smell it,” says Snodgrass. “If you are standing there without your space suit, you’re not going to notice the smell, you’re just going to notice the lack of air.”