Comets likely didn't deliver life's ingredients to Earth, study finds

A Cambridge-led study found that hydrogen cyanide carried by comets would have been mostly vaporized on impact due to extreme heat, challenging a century-old theory on the origins of life. Researchers suggest asteroids or Earth's own chemistry as more likely sources.

• Researchers modeled comet strikes, atmospheric interactions and gravitational paths
• HCN is the only starter molecule comets carry in useful amounts
• Only comets wider than about 300 feet could survive the early atmosphere
• Asteroids or local synthesis on Earth are more likely sources