Why in the News?

A recent study led by Stanford University chemist Richard Zare has introduced a novel perspective on the origins of life on Earth, providing an alternative to the well-known Miller-Urey hypothesis.

About the Miller-Urey Hypothesis

• The Miller-Urey hypothesis emerged from an experiment conducted in 1952 by chemists Stanley Miller and Harold Urey.
  • It sought to simulate the conditions of early Earth to understand how life could have originated.
• They used a mixture of water, methane, ammonia, and hydrogen, gases believed to be present in the early Earth’s atmosphere.
• The setup also included an electric spark to simulate lightning, which they hypothesized could have played a role in the formation of organic compounds.
• Results: The experiment successfully demonstrated that organic molecules, like amino acids, essential for life, could form when an electrical spark (simulating lightning) was applied to the gas mixture.
• Impact and Debate:
  • The experiment was a landmark in understanding life’s chemical origins.
  • However, over time, critics argued that real lightning would have been rare and mostly occurred over open ocean, where organic compounds would have been quickly dispersed.
  • This led to the questioning of lightning as the primary trigger for life’s origins.

Life on Earth and the Role of ‘Microlightning’ in Water Droplets

• The Stanford study shows that when water droplets divide, they develop opposing electrical charges—larger droplets become positively charged, and smaller droplets become negatively charged.
• When these oppositely charged droplets come close together, tiny sparks (termed micro-lightning) can leap between them, mimicking the electrical phenomena that occur in thunderstorms.
• Experimental Evidence:
  • In the experiment, when water sprays were mixed with nitrogen, methane, carbon dioxide, and ammonia, they produced organic compounds like glycine and uracil, similar to those in the Miller-Urey experiment.
  • Microlightning from water sprays can therefore generate organic compounds, providing a plausible and common natural process for the origin of life.
• These microlightning events could have been far more common and accessible than lightning strikes, offering an alternative mechanism for the generation of life-building organic molecules.

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