Scientists have uncovered chemical traces of life in rocks more than 3.3 billion years old, pushing the origins of oxygen-producing photosynthesis nearly a billion years earlier than previously believed. The discovery, reported by The Daily Galaxy, was made possible by pairing advanced chemical analysis with machine learning tools designed to detect the faintest molecular fingerprints of ancient biology.
The project, led by the Carnegie Institution for Science, trained artificial intelligence to recognize subtle biosignatures that would normally be erased by billions of years of heat, pressure, and tectonic recycling. Traditional fossils often cannot survive this deep geological churn, but chemical echoes can. With AI sorting through molecular patterns, researchers were able to identify signals of early photosynthesis in rocks as old as 2.5 billion years.
According to Dr. Robert Hazen, a senior scientist at Carnegie and co-lead author, ancient life leaves behind more than visible fossils. It leaves chemical shadows hidden in the rock record, and machine learning finally makes those shadows readable.
The study also incorporated fossil samples from Michigan State researcher Katie Maloney, who provided more than a billion-year-old seaweed specimens from Canada’s Yukon region. These fossils represent some of the earliest complex organisms known and helped calibrate the AI models.
One of the most striking outcomes is the revised timeline for oxygen-producing photosynthesis. Long thought to have emerged around 2.3 billion years ago, the new evidence suggests this process may have begun at least a billion years earlier. That shift reshapes scientists’ understanding of how quickly early life evolved and how Earth’s atmosphere began transitioning toward oxygenation.
The technique could also transform the hunt for extraterrestrial life. The same AI system could be used to analyze samples from Mars, Europa, or other worlds where geological processes may have destroyed traditional fossils but left behind chemical residues. If life ever existed elsewhere, its chemical signatures might be detectable with the same approach.
Researchers say this breakthrough opens a new window into Earth’s earliest biosphere and offers a powerful new tool for exploring life across the solar system.