Study challenges comet hypothesis for Earth's origin of life
Cambridge researchers model comet impacts and find that intense entry conditions likely destroy key organic molecules, making delivery of life's building blocks by comets highly improbable.
A new modeling study led by researchers at the University of Cambridge suggests that comet impacts are unlikely to have supplied the organic compounds needed for the origin of life on Earth. The analysis focused on hydrogen cyanide (HCN), a molecule commonly found in comets and considered a prebiotic building block. The team calculated that the extreme heat and pressure generated during atmospheric entry would destroy most of the HCN, requiring an almost impossible combination of speed, angle, and post-impact conditions for any significant amount to survive.
"The survival of hydrogen cyanide would be a one-in-a-million fluke," said lead author Richard Anslow in a statement.
The researchers argue that if HCN, one of the more resilient prebiotic molecules, cannot endure comet entry, other organic compounds would be even less likely to persist. While the findings cast doubt on the comet-delivery hypothesis for Earth, the authors note that Mars' thinner atmosphere might have provided a less hostile environment for similar processes.
The study was published in the journal Scientific Reports.