Scientists have traced the Last Universal Common Ancestor (LUCA) of all life on Earth back to around 4.2 billion years ago, during the tumultuous Hadean Eon. This single-celled organism had surprisingly advanced features, including a sophisticated immune system, which challenges the notion that early life was simple. LUCA's ability to thrive in such extreme conditions offers valuable insights into the origins of life and the potential for complex life to develop quickly, even in harsh environments, raising intriguing possibilities for the search for extraterrestrial life.
