RNA Sparks Life: Earth’s Habitability Window Opens Around 4.33 Billion Years Ago

A Nature Communications study using 3D impact modeling suggests Earth cooled enough for an RNA-based origin of life between about 4.4 and 4.3 billion years ago, with optimal conditions around 4.33 billion years ago. While this narrows the timeline for the RNA world, it doesn’t pin down the exact moment life began, since liquid water, nutrients and other environmental factors must align; zircon evidence of liquid water by ~4.4 Ga supports the window and the work also informs questions about habitability on Mars.