Life’s Origins 157have been produced in many other places in the universe. Some scientists even speculate
that the earth was “seeded” with organic compounds from space and that sparked the ori-
gin of life, although given how easily they are made here on earth, we don’t need this more
complex hypothesis.
FIGURE 6.3. An apparatus like this was used by Stanley Miller and Harold Urey in 1953 to simulate the synthesis
of complex organic compounds on the early earth. The system was evacuated of air, then the large flask held
an “atmosphere” rich in carbon dioxide, water, nitrogen, ammonia, and methane (but no oxygen). Sparks
from electrodes simulated lightning. The product of this reaction then flowed through the condenser and
accumulated in the flask, which became a brew of “primordial soup.” After about a week, the clear solution
had turned into a thick murky brown sludge full of newly synthesized organic compounds, including many
of the amino acids necessary to build life. (Photo courtesy S. Miller)
500-cc flask CondenserTungsten electrode Tungsten electrodeStopcock for withdrawing samples during runTrap5-liter flask