The original version of this story appeared in Quanta Magazine.
Ten years ago, the European Space Agency’s Rosetta probe pulled up alongside a dusty, icy lump the size of a mountain. The probe would follow its quarry, a comet called 67P/Churyumov-Gerasimenko, for two years as onboard instruments caught and analyzed the dust and gas streaming away from the comet. Scientists sought hints about how our solar system came to be—and about the origin of one class of molecules in particular.
Organic molecules—compounds containing carbon—abound on Earth, especially in the bodies of living things. They’re often called the building blocks of life, and for good reason: Carbon atoms can chemically bond to