New study challenges theory that comets seeded life on Earth

The popular theory that comets were crucial in kick-starting life on Earth billions of years ago may not hold up, according to new computer simulations that counter decades of scientific thinking. The finding suggests the fragile organic molecules supposedly carried by the icy objects would have been destroyed on impact, upending an established origin of life theory that dates back to at least 1961. The broader idea that the ingredients for life arrived from space, known as panspermia, is even older and was scientifically postulated in 1908. Life on Earth requires complex organic molecules, but it’s unclear whether our early planet had enough of the raw materials needed for prebiotic chemistry — the chemical reactions that produce the building blocks of life. Comets are made of dust and ice but are also known to contain organic material.