Final answer:
Science posits that life on Earth originated from natural processes about 3.7 to 4.1 billion years ago in suitable prebiotic conditions, leading to the first cells. Various scientific disciplines support different evolutionary hypotheses, with the consensus pointing towards development from simple molecules to complex life encapsulated in the concept of LUCA.
Step-by-step explanation:
Contemporary science views the origin of life on Earth through natural processes, guided by the principles of astrobiology. About 3.7 to 4.1 billion years ago, conditions on a prebiotic Earth facilitated the emergence of the first cells, which had all properties essential to life. These conditions may have been replicated on other planets, giving rise to optimism that life exists beyond Earth. Scientists propose different hypotheses for life's origins, informed by evidence across various disciplines. The scientific narrative moves from simple molecular reactions to the biological complexity seen in LUCA (the universal common ancestor), which emerged from an RNA world to a more complex cell with replicating DNA and metabolism dependant on ATP.