Earth’s rotation has been slowing down for about 4.5 billion years, causing its days to lengthen over time. This phenomenon may have played a crucial role in the oxygenation of the planet’s atmosphere, according to a recent study.
The Great Oxidation Event, which occurred around 2.4 billion years ago, is widely considered a turning point in the history of life on Earth. However, scientists have long wondered how this event took place and what factors controlled its timing. The new research suggests that Earth’s slowing rotation may have had an important impact on the pattern and timing of oxygenation.
The study found that the rate at which Earth spins – measured by day length – influenced the release of oxygen from bacterial mats. When the planet was still relatively young, with 18-hour days, cyanobacteria could only produce oxygen during a limited period each day. This competition between microbes may have contributed to the delay in oxygen production on early Earth.
To test this hypothesis, researchers conducted experiments and measurements on the microbes and performed detailed modeling studies. Their findings revealed that lengthening days were linked to an increase in oxygen levels – not just the Great Oxidation Event, but another atmospheric oxygenation event around 550-800 million years ago.
The study’s authors believe that this discovery highlights a fundamental link between day length and oxygen production. By linking laws of physics operating at different scales, from molecular diffusion to planetary mechanics, researchers have shed new light on Earth’s history and the emergence of life on our planet.
Source: https://www.sciencealert.com/earths-rotation-is-slowing-down-and-could-explain-why-we-have-oxygen