Miller and Urey experiment

  • scientists (specifically Darwin and Oparin) believed that life originated from the early ocean, or the primordial soup

    • in the soup, various chemical reactions took place, which eventually produced living cells

      • was a good theory but didn’t hv evidence to back it up

  • Miller Urey experiment aimed to change this

    • wanted to mimic early Earth’s conditions to see what happens

    • also wanted to test if chemistry really can give rise to complex molecules of life

  • designed an apparatus to mimic or simulate the ancient water cycle

    • water was used to mimic the ancient ocean, and was gently boiled to mimic evaporation

    • gases in the atmosphere - water vapour, methane, ammonia, & hydrogen

      • simple gases which scientists thought were abundant in ancient Earth

    • added condenser to cool the water molecules

      • allowed the water to turn into waterdrops and return back to the ocean as rain

    • added sparks to atmosphere to mimic the various sources of energy that would’ve been present on ancient Earth (such as lighting storms, sunlight & geothermal heat)

  • after running experiment for a week - ocean became brownish-black

    • analysis revealed that many complex molecules had been produced, such as amino acids

scientists don’t know for sure that the gases used in the experiment, really were the most common gases in early Earth

  • because of this, various experiments hv been carried out that demonstrate that the molecules of life (amino acids?) can form in a variety of environments, with different starting chemicals & different sources of energy

sugars, lipids & amino acids have even been found on asteroids

  • suggests that the molecules of life are formed throughout the solar system

Experiment was significant for 2 reasons

  1. demonstrated that molecules of life rlly can form under ancient-Earth like conditions

  2. provided evidence that changed speculation, into legitimate testable science