"New evidence shows the number of ancient, large celestial bodies that crashed into Earth was up to 10 times higher than previously believed. This finding has led a team including a UC Riverside scientist to conclude that these collisions likely shaped the development of Earth’s chemistry early in its history.
The team’s work is detailed in a recent Nature Geoscience article. Impacts by asteroids or comets during the earliest years of Earth’s history likely contributed to the beginnings of life and its early evolution, yet later they delayed the development of more complex life forms that require oxygen.