Did comets bring building blocks of life to Earth? Scientists aren't so sure anymore
However, while comets bringing the building blocks of life to Earth is "kind of a romantic idea," according to Anslow, the University of Cambridge researcher added that the team's results suggest that is highly unlikely.
- "Historically, scientists thought that comets were important for the origin of life on Earth, because they carried carbon and nitrogen-bearing molecules, so these giant space snowballs were almost like a 'get-out-of-jail-free card' that brought all the molecules a planet would need to seed life," said Anslow in a statement.
- For over a century comet impacts had been considered a prime suspect in the search for what brought the building blocks of life to Earth.
- Complex organic molecules are the fundamental building blocks of biochemical compounds such as nucleobases, amino acids, sugars and so on that act as the machinery for biochemistry on Earth.
New research shows that comets almost certainly did not bring the chemical building blocks of life to our planet.
Scientists have found asteroids to be rich in those molecules – for example, the sample of material brought back by the OSIRIS-REx mission from the near-Earth asteroid Bennu contained all the building blocks of RNA.
- New research led by planetary scientist Richard Anslow of the Institute for Astronomy at the University of Cambridge has now seemingly ruled out comets as the origin of complex organic molecules on Earth.
- However, researchers are coming around to alternatives, either that all the pre-biotic chemistry that resulted in life took place on Earth without requiring material from space, or asteroids instead brought those important molecules to Earth.
- An artist’s impression of a comet crashing into the early Earth (Image credit: Scarlett White) The problem is that comets are generally moving at too great a velocity.
- Anslow and his colleagues found that, in general, comets travel too fast and enter Earth’s atmosphere at too sharp an angle for complex organic molecules to survive.
- Stripping the romance from the Earth's turbulent past Comet impacts on Earth were much more frequent in the first half-billion years of the solar system ’s existence, when there were still lots of debris leftover from the formation of the planets.
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