The oldest traces of life on Earth An international team, with the researchers Tor Grenne at the Geological Survey of Norway and John F. Slack from USGS on board, has recently found relics on the world’s oldest known life. These are traces of microscopic organisms that lived at hot springs down on the seabed more than 3770 million years ago. Possibly they can be as old as 4280 million years. By comparison, the age of the earth is around 4600 million years old, and the oldest traces of life on land about 460 million years. The primitive organisms themselves are not preserved, but they can be traced through thin threads and pipe-like structures in fine-grained iron minerals in the rock. The tiny structures have characteristic shapes and branches that correspond to what we find around metal-rich hot springs on long-term dispersal backs on the seabed today. Here, very special bacteria live by oxidizing iron and turning it into rust, a kind of iron oxide that eventually transforms into hematite. The researchers have emphasized systematically to investigate whether the findings may stem from non-biological processes, such as temperature and pressure changes in the rocks after they were deposited. The conclusion is that the structures must originate from microorganisms. Another indication is that along with particular structures are graphite, apatite and carbonate, which are typical of converted biological material, as well as instances of small round structures, so-called rosettes and granules, which are formed during the degradation of bacterial residues on the seabed. These are identical to discoveries in younger rocks through much of the geological history of the Earth, including rocks the researchers have studied in North America, Western Australia and Norway. At Løkken in Central Norway there are microscopic wire-shaped traces of bacteria that...