Guest Post: Life as old as the Earth? The earliest evidence for living things

stromatolite-fossil-james-st-john-flickr-ccc2.jpg
Cross-section of a fossil stromatolite © James St John, flickr, https://creativecommons.org/licenses/by/2.0/

The history of life on Earth is almost as long as the history of Earth itself. The most precise scientific dating methods tell us that our planet formed 4567 million years ago, although there are no rock samples preserved from this ancient and chaotic time. The oldest known Earth materials are about 4300 million years old, and are found in the remote deserts of western Australia. The oldest probable evidence for life on Earth has been dated between 3700 and 3800 million years, in west Greenland, and is so sophisticated that the history of life on earth must extend much further back. These observations suggest that life is a fundamental property of our planet, a feature which makes the Earth very different from its immediate rocky neighbours. Continue reading