The discovery of 3.5 billion year old fossil evidence of microorganisms suggests life on Earth could have began on land in a hot spring, researchers say in a new study.
- Why it matters: The fossils push the geological record of primitive terrestrial life back about 580 million years and challenge the current theory that life on the planet originated in hydrothermal vents on the ocean floor. The Western Australia rock formation where the fossils were found could also provide a guide for looking for life on Mars.
- Where did we come from? "There are cases to be made for both a salt water and fresh water beginning to life but the jury is still out on where life started," says astrobiologist Robert Hazen, who wasn't involved in the study.
- The big question: How much earlier did life begin here?