In the Natural Sciences, abiogenesis is the question of the origin of life, the study of how life on earth can develop from non-living. According to the scientific consensus, abiogenesis occurred between 4.4 billion years ago and 2.7 billion years ago today. 4.4 billion years ago, the beginning of this time period, is when water vapor liquefies. 2.7 billion years ago is when constant carbon ,iron and isotope ratios indicate that minerals and sediments are of biological origin, while biological indicators indicate photosynthesis.
This topic also includes panspermia and extraterrestrial (exogenous) theories that suggest that life from the solar system or extraterrestrial life may have occurred during the 13.7 billion years of development of the universe since the Big Bang.
Although the study of the origin of life has a huge impact on biology and human understanding of the natural world, it is a limited area of research. Advances in this field are often slow and intermittent, although many people are intrigued by the importance of the problem being investigated. Among the many proposed theories, iron-sulfur theory (metabolism first) and RNA world hypothesis (genes first) are the most popular.