Scientists have a new idea for how Earth got its oxygen: It’s because the planet slowed down and days got longer. A study published Monday proposes and puts to the test the theory that longer, continuous daylight kick-started weird bacteria into producing lots of oxygen, making most of life as we know it possible. They dredged up gooey purple bacteria from a sinkhole in Lake Huron and tinkered with how much light it got. The more continuous light the smelly microbes got, the more oxygen they produced. Just how Earth’s great oxygenation event started has long been a scientific mystery.
New theory: Earth’s longer days kick-started oxygen growth
