A peer-reviewed three-dimensional heat model in Nature Communications marks about 4.33 billion years ago for a proposed RNA World, a stage at which RNA would have been the main replicating substance. Live Science reports the same sweet spot, and says Earth may have been suitable as early as 4.4 billion years ago once heavy bombardment eased. In the model, global sterilization events last until about 4.4 billion years ago. Estimates for life's emergence still run from about 3.8 billion years ago into the Hadean.
A peer-reviewed three-dimensional heat model marks about 4.33 billion years ago for a proposed RNA World. Live Science reports that same sweet spot and gives the phrase: a hypothetical time when RNA was the primary replicating substance. RNA is a chemical cousin of DNA that can both store a sequence and help reactions along. The two outlets are describing one dating result, not two origins stories.[1], [2]
In the model, global sterilization events last until about 4.4 billion years ago. Live Science says Earth may have become suitable for the RNA World as early as 4.4 billion years ago, once extreme bombardment by the rocky leftovers of planet formation had largely eased. Oleg Abramov, Anna Medvegy, Barbara Kremer and Stephen J. Mojzsis model the thermal evolution of Hadean crust under that late bombardment. The Hadean is Earth's first geologic stretch, before 4 billion years ago.[1], [2]
By tracking the near-surface thermal stability of nucleotides, peptides and lipids, the authors conclude that a proposed RNA World appeared at about 4.33 billion years ago. Nucleotides are the building blocks of RNA. Estimates for when life emerged still run from about 3.8 billion years ago to the Hadean, at or before 4.0 to 4.5 billion years ago. The paper dates a habitable window in a heat model. It does not produce a fossil.[1]
