A group of scientists from the University of California, Los Angeles, and the University of Wisconsin may have found the oldest evidence for life on Earth, according to a new study published in the Proceedings of the National Academy of Sciences.
This team found the evidence in samples of microorganisms on a tiny, nearly 3.5-billion-year-old piece of rock uncovered in Australia. Scientists first unearthed the tiny “microfossils” in 1993. However, it was not until the recent study that scientists managed to determine the fossils were biogenic, meaning they had a biological origin rather than a mineral one.
To make that discovery, the researchers used a secondary ion mass spectrometer to examine the ratio of carbon isotopes within the fossils. That study not only revealed the fossils’ biological origins, but it also showed that they are a staggering 3.465 billion years old.
“By 3.465 billion years ago, life was already diverse on Earth; that’s clear—primitive photosynthesizers, methane producers, methane users,” said lead author J. William Schopf, a researcher at the University of California, Los Angeles, according to Newsweek. “These are the first data that show the very diverse organisms at that time in Earth’s history, and our previous.”
This new finding shed light on when life may have first emerged on Earth, a topic that is heavily debated throughout the scientific community. While scientists are not yet sure, they believe the fossils formed when there was little oxygen in Earth’s atmosphere. In fact, it is likely that oxygen would have killed the ancient organisms.
Not only do the fossils help build a timeline for when life first emerged on this planet, but it also could shed light on where else life could exist in the universe. As life evolved so early in our planet’s history, it is likely it exists somewhere else in the vast cosmos.