Comets may not have brought life's building blocks to Earth
A study from the University of Cambridge suggests that prebiotic molecules might not survive high-speed cometary impacts on the planet.
A century-old theory suggesting that comets delivered the building blocks of life to Earth may be incorrect, according to a study published in Scientific Reports last week, the New York Post reported.
Researchers at the University of Cambridge found that the chances of prebiotic molecules surviving a comet's high-speed impact with Earth are slim. The study suggests that comets typically travel too fast and strike at angles that cause molecules to vaporise.
Lead author Dr Richard Anslow from the Institute of Astronomy at Cambridge said the idea that comets brought necessary molecules was a romantic idea, but results suggest it is highly unlikely.
Dr Anslow stated that even if some building blocks survived in a one-off fluke, the concentration might not be high enough to create life. He noted it would require a one-in-a-million occurrence involving the right speed, angle, and chemical concentration.
The researchers said molecular seeds of life could have come from other sources, such as asteroids, which hit Earth more frequently. They also noted that comets might be more likely to deliver molecules to Mars due to its smaller size and thinner atmosphere.
Dr Anslow said the findings do not prove life did not start on Mars, but suggest it would be unlikely if it happened on Earth and not on Mars. He added the alternative is that it may not have happened on either planet.