Hadean

Cosmic bombardment may have opened Earth's crust for prebiotic chemistry

Cosmic bombardment may have opened Earth's crust for prebiotic chemistry Gaby Clark Scientific Editor Robert Egan Associate Editor Asteroids and planetesimals regularly bombarded Earth between about 4.6 billion and 3.5 billion years ago, during the Hadean and Archean eons. Because few rocks today are more than 4 billion years old, our understanding of the planet's environment during that time is limited. However, samples from the moon and its cratered surface hint at the period's rate of...