Abiogenesis is the scientific theory that explains how life on Earth began from non-living matter. It suggests that simple organic compounds formed through natural processes, eventually leading to the development of more complex molecules. These molecules may have combined and evolved over time, resulting in the first simple living organisms. This process is thought to have occurred around 3.5 to 4 billion years ago, during a time when the Earth had a very different environment. Researchers study various factors, such as chemical reactions, environmental conditions, and energy sources, to understand how life could emerge from inanimate substances.