- This classic experiment, conducted in 1953, demonstrated that a mixture of just water vapor and some simple gases (specifically, methane, ammonia and hydrogen), merely subjected repeatedly to electrical sparks over time, resulted in chemical products including a number of amino acids. Amino acids are the very “building blocks” from which life-essential proteins are formed. The first image, below, summarizes the fundamentals of this experiment. The second image, below, shows the experimental design.
- Other than the basic design described above, no other “help” was given to lead to the formation of the amino acids or to cause any specific chemical reactions. Yet, with the repeated input of electrical energy, the necessary chemical reactions just occurred, and amino acids formed – simple organic compounds, but critical to Earth-based life.
- The Miller-Urey experiment was intended to simulate conditions believed at the time to be present on early Earth – the gases simulating the atmosphere, and the electrical sparks simulating lightening (or another energy source). To this day, debate continues on the make-up of the atmosphere of early Earth (at various stages), and it may have differed significantly from the highly reducing nature supposed in the Miller-Urey experiment. However, many generally similar experiments have been performed in the decades since, with various different such suppositions and consequent reactant selections, and have also resulted in formation of amino acids and other simple biologically significant molecules (for some detailed information on this, see, e.g., http://ncse.com/files/pub/creationism/icons/gishlick_icons1.pdf).
- The Miller-Urey experiment, and others to follow, may be taken to strongly suggest that simple biologically significant molecules, including amino acids, can develop, or evolve, naturally under sets of conditions that may have existed not only on early Earth, but potentially elsewhere in the solar system and beyond. It is, of course, a giant leap from the development of amino acids to the development of even the simplest forms of life. Furthermore, amino acids, and other biologically significant molecules, could potentially have been “seeded” on Earth from other sources, such as meteorites (in which they have been found); this would be in accordance with the hypothesis of panspermia (itself intriguing). None the less, the Miller-Urey experiment is taken by many to powerfully suggest the possibility of life developing in increments over time, or evolving, naturally from non-living matter (on Earth and, potentially, elsewhere): abiogenesis…life from non-life.
- Resources include: https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment.
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