9. The Origin of Life
The question of how life first emerged on Earth remains one of science’s greatest unsolved puzzles. Multiple theories—such as the primordial soup and hydrothermal vent hypotheses—attempt to explain how simple molecules gave rise to self-replicating organisms. Yet, no laboratory experiment has successfully bridged the gap from non-living chemistry to living cells. This enduring enigma shapes our search for life elsewhere in the universe, pushing scientists to reconsider what it means to be alive. Read more at Nature.