The Great Oxidation Event: When Earth's Life-Giving Atmosphere Became a Planetary Killer

Some 2.4 billion years ago, the very breath of emerging life became the instrument of mass death — photosynthetic microbes quietly exhaled oxygen into an atmosphere that had never known it, and in doing so, erased the vast majority of Earth's living world. This paradox, known as the Great Oxidation Event, stands as a reminder that progress and catastrophe are often the same event seen from different vantage points. New evidence from an ancient asteroid crater in South Korea is now helping scientists understand not just how this oxygen accumulated, but how the violent geology of early Earth may