Do we have cosmic dust to thank for life on Earth?

An asteroid is breaking up, producing a lot of dust, which reaches the Earth eventually. (Image: NASA / JPL-Caltech) - It might be that what set prebiotic chemistry in motion and kept it going in the early days of the Earth was dust from outer space accumulating in holes melted into ice sheets. Researchers at ETH Zurich and the University of Cambridge have used a computer model to test this scenario. Before life existed on Earth, there had to be chemistry to form organic molecules from the chemical elements nitrogen, sulphur, carbon and phosphorus. For the corresponding chemical reactions to start and be maintained, these elements had to be present in abundance - and constantly replenished. On the Earth itself, however, these elements were and still are in short supply. In fact, the elementary building blocks of life were so rare that chemical reactions would have quickly become exhausted, if they indeed ever managed to get going at all.