Cosmic dust concentrated and accumulated on the early Earth
Life appeared surprisingly early on our planet, despite the fact that the early Earth was deprived of the necessary chemical components for the emergence of life.
Prebiotic chemicals such as sugars and amino acids are known to form in asteroids and comets. Therefore, scientists assumed that the Earth could have been «seeded» materials for life as a result of collisions with asteroids and comets. However, new research shows that cosmic dust also played an important role in the emergence of life on the young planet.
It was previously thought that cosmic dust that accumulated on the Earth's surface was not a major source of prebiotic material because it was dispersed throughout the planet, as opposed to being concentrated at comet and asteroid impact sites. New research, however, has found that cosmic dust can accumulate and concentrate in sediments, creating favorable conditions for the emergence of life.
Scientists assessed the rate of accumulation of cosmic dust in the early period of the Earth and modeled its accumulation in the corresponding sedimentary layers. The results showed that the amount of dust accumulated in the sediments significantly exceeds the amount of prebiotic material carried by comets and asteroids. In addition, the researchers found that the processes of melting and freezing of glacial areas can significantly increase the concentration of chemicals in cosmic dust. For example, in early subglacial lakes the concentration of prebiotic material in the dust was much higher than at the sites of comet and asteroid impacts. These discoveries indicate that cosmic dust may have played a much more important role in the emergence of life than previously thought.
Nevertheless, life on the early Earth and the mechanisms of its origin still remain mysteries. But certainly without the influence of extraterrestrial chemistry delivered by cosmic dust, life on Earth would be impossible. It is from dust that the building blocks of life arose, and it is because of this that we can today trace the emergence of living organisms on Earth to the early chemical composition of dust in the Solar System.