A long-held theory that comets delivered the chemical building blocks for life to early Earth is being challenged by new research from the University of Cambridge. The study, published in Scientific Reports, examined whether icy comets packed with carbon could safely transport fragile organic molecules to a young planet. The researchers concluded they could not.
For more than a century, scientists have suggested that comets may have seeded Earth with carbon- and nitrogen-bearing molecules needed for life to begin. Lead author Dr Richard Anslow, from Cambridge’s Institute of Astronomy, said the idea had long been treated almost like a “get out of jail free card” for the origins of life. “It’s kind of a romantic idea, but our results suggest it’s highly unlikely,” he said in a statement.
According to the study, the extreme heat and pressure generated when a comet strikes a planet would instantly destroy the delicate molecules required for life. Rather than a steady rain of life-giving ingredients from space, the researchers believe any successful delivery would have been an extremely rare event.
“It would really have to be a one-in-a-million occurrence, because not only would you need an impact at just the right speed and just the right angle, you would also need everything to happen after that point, in terms of the concentration and the speed at which the chemical origins of life got going,” Anslow said. “We can’t rule out for certain that it happened that way. But it seems to be a really rare occurrence — at best, a one-off fluke.”
With the comet theory heavily challenged, scientists are now looking closer to home. Experts suggest the essential ingredients for life may have formed on Earth itself, or arrived through asteroid impacts, which were far more frequent and less destructive than comet crashes.
The team also examined Mars and concluded that similar impacts would likely have failed there too. “This is not to say it definitely happened on Mars, of course, but suggests it would be unlikely if it happened on Earth and didn’t happen on Mars,” Anslow said. “Or the other, perhaps more likely, alternative is that it didn’t happen on either planet.”
Original Source: https://www.ndtv.com/science/new-study-suggests-comets-didnt-bring-life-to-early-earth-after-all-12274001#publisher=newsstand
Category:
Tags:
Publish Date: 2026-11-03 06:40:00
