In Jeffrey Bada’s laboratory at the University of California, San Diego, there’s a cardboard box containing the earliest evidence of how life began on Earth. The box holds hundreds of tiny vials filled with grimy, brown residues collected in the early 1950s by a University of Chicago graduate student named Stanley Miller. Each vial is marked with a page number corresponding to a notebook where Miller recorded an experiment undertaken with his adviser, the Nobel Prize-winning chemist Harold Urey.
Their goal was to synthesize amino acids — the building blocks of life — as they might have been created on early Earth. The results launched a hunt for life’s origins that’s now uncovering these building blocks in surprising places, like the surface of comets and in deep-sea hydrothermal vents.
A Laboratory Earth
The modern origin question has bedeviled scientists since Charles Darwin proposed his theory of evolution in the 19th century. If all modern species evolved from earlier life-forms, the branching must have begun with some common ancestor. Darwin speculated that our microbial Eve arose from a “warm little pond with all sorts of ammonia and phosphoric salts.” Eight decades later, Urey sought to be more precise. He enlisted research on early planetary conditions to show how interactions between the atmosphere and oceans might have produced an organic “primordial soup.”
