Do comets smell like llamas?
May 31, 2017

Do comets smell like llamas?

We’ve been giving out Rosetta smelly comet postcards at the UK Space Conference and asking people what they think a comet smells like. We’ve added the responses to our list from the European Parliament in November and EuroScience Open Forum (ESOF) 2016 in Manchester, back in July last year.

The answers are wide and varied:

Stroking llamas in an animal sanctuary. Moss. Horse pee. My grandfather. Dusty hi-fi. Madrid Airport. Face powder. Hospitals. Almond biscuits. Toilet block freshners. Worked metal and fried meat. Old Chanel. Carbon. The Jorvik Viking Centre. Cut grass. Talcum powder. A car air freshener that’s been run over by a truck. Chalky. Stables. Sandalwood. Plasticine. Musty. Dodgy aftershave. Toilet paper. Patchouli. The London Dungeon. Dust. Burnt essence. Indian Ashram. Toilet cleaner. Coal. Old felt toy. Incense. Earthy. Cat litter tray. Air-bag packaging. Hand wipes. Horse poo. Old-fashioned soap. Rotten animals. Playdoh…

The smell recreates the chemical profile of comet 67P/Churyumov-Gerasimenko, as measured by the mass spectrometer instruments on the Rosetta orbiter and Philae lander. The chemical composition of the comet mostly:

  • H2O (water)
  • CO (carbon monoxide)
  • CO2 (carbon dioxide)
  • H2S (hydrogen sulphide)
  • NH3 (ammonia)
  • CH2O (formaldehyde)
  • CH3OH (methanol)
  • SO2 (sulphur dioxide)

Rosetta has discovered many other rare molecules in the comet, including amino acids that are the building blocks of proteins and all life on Earth.