What process might have caused the first cells to spontaneously generate over long periods of time?

Answer 1

The theory of abiogenesis (aka biopoiesis) suggests that amino acids, which form naturally under the proper chemical conditions, could have joined to form self-replicating chains such as RNA. Once formed, these molecules could have evolved into more complex forms such as DNA.

Answer 2

One theory is that the first cells may have originated from a primordial soup of organic molecules where chemical reactions and interactions led to the formation of simple, self-replicating structures. Another possibility is that cells may have arisen near deep-sea hydrothermal vents where mineral surfaces could have catalyzed the formation of cell-like structures. Overall, the exact process is still a topic of active research and debate in the field of abiogenesis.