Radiation can make the ice act like a liquid which favours the growth of organic molecules. The researchers from Hokkaido University in Sapporo, Japan found that ice in space behaves like a liquid at -2100C and -1200C temperature range. This favours the formation of the organic compounds that include prebiotic molecules along with dust for the formation of planets.
Scientists do not have a definite answer to that but they do know that Earth’s atmosphere in the ancient times was extremely different from the present time. After conduction of various experiments, scientists have deduced the fact that the Earth’s atmosphere has changed over time to accumulate life.