Study Places Earth's RNA World Sweet Spot at 4.33 Billion Years Ago
Updated
Updated · Gizmodo · Sep 22
Study Places Earth's RNA World Sweet Spot at 4.33 Billion Years Ago
3 articles · Updated · Gizmodo · Sep 22
Summary
A Nature Communications study led by Oleg Abramov estimates Earth’s crust became most thermally suitable for an RNA world about 4.33 billion years ago, narrowing the likely window for life’s earliest chemistry.
A 3D model of impacts from 4.5 billion to 3.5 billion years ago found that declining asteroid bombardment let the upper crust cool into a range where RNA and other key molecules could remain stable.
The team put the broader habitable interval at roughly 4.4 billion to 4.3 billion years ago, but said thermal suitability alone was not enough because liquid water, reduced nitrogen, pH, salinity and mineral settings also mattered.
Zircon evidence showing liquid water by about 4.4 billion years ago already fits the timeline, and Abramov said more mantle, zircon and lunar samples could further test it.
The work could also guide habitability studies beyond Earth, including Mars, where Abramov said a life-friendly window may have opened earlier because the planet is smaller and faced slower impacts.