A UCLA study released today says life on Earth likely existed at least 4.1 billion years ago, which is 300 million years earlier than previously believed.
Mark Harrison, co-author of the study and a geochemistry professor at UCLA, said the latest research shows that life on our planet “may have started almost instantaneously” following the planet’s creating 4.54 billion years ago.
“Twenty years ago, this would have been heretical,” Harrison said. “Finding evidence of life 3.8 billion years ago was shocking.”
But he said the new research lends credence to the theory that “with the right ingredients, life seems to form very quickly.”
According to the UCLA research, which was published online today by the journal Proceedings of the National Academy of Sciences, life likely existed on the planet prior to the bombardment of the inner solar system that created the large craters on the moon 3.8 billion years ago.
“If all life on Earth died during this bombardment, which some scientists have argued, then life must have restarted quickly, according to study co-author Patrick Boehnke, a graduate student in Harrison’s laboratory.
The research was based on a study of thousands of zircons — heavy, durable minerals that scientists said can act as miniature time capsules by capturing and preserving their immediate environment.
One of the zircons was found to contain graphite — or pure carbon, a key component for life, researchers found. They determined the zircon was 4.1 billion years old based on its ratio of uranium to lead, and the graphite found inside is likely much older.
Harrison noted that while simple life likely formed very quickly on Earth, it likely took millions of years for that life to evolve to the point of being able to photosynthesize. The carbon detected in the zircon indicates the presence of photosynthetic life, researchers said.
Harrison suggested that the research also suggests that life in the universe could be “abundant.”
