WET rocks hurtling around the solar system may have given life on Earth its addiction to left-handed building blocks.
Almost all life on Earth uses left-handed amino acid molecules instead of their right-handed counterparts. In the 1990s, scientists found that meteorites contain up to 15 per cent more of the left-handed versions too. So space rocks bombarding the early Earth may have biased the planet’s chemistry. A linked theory has it that polarised starlight can preferentially destroy right-handed amino acids on asteroids, though this alone cannot explain the strength of the bias on meteorites.
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