During its first few hundred million years, Earth was a hostile target. Asteroids, comets, and leftover planetesimals, smaller bodies remaining from planet formation, relentlessly battered the planet, generating intense heat that could sterilize the shallow crust and destroy chemical precursors to life.
For biological systems to take root, their delicate molecules required prolonged periods to form, remain intact, and interact. Researchers are particularly interested in finding when this stability emerged for the RNA World, a proposed early stage in biological history before DNA assumed its modern genetic role. Because RNA can hold genetic information and perform some of the chemical work needed for replication, scientists consider it a leading candidate for an early biological system.
A three-dimensional computer model published in Nature Communications traces how the planet eventually settled down enough to support these fragile molecules. By simulating how impacts heated the crust between 4.5 and 3.5 billion years ago, researchers found that frequent global sterilization events continued until about 4.4 billion years ago.
To read more, click here.