The greatest challenge facing astrobiologists is that there is only one planet known to us that has life. Of all the bodies of the Solar System, only Earth has a dense atmosphere, liquid water on its surface, and the organic chemistry that supports life.

However, these conditions did not exist billions of years ago when Earth was still young. While the nebula from which the planets formed was rich in volatile elements, the high temperatures in the inner Solar System largely prevented them from condensing, leaving them mostly in a gaseous state.

As a result, these elements were not incorporated into the solid rocky materials from which the inner planets formed. Only celestial bodies that formed farther from the Sun retained the substances essential to life, which raises questions about how and when they were introduced to Earth.

In a new study, researchers from the University of Bern showed for the first time how the chemical composition of primordial Earth was complete three million years after it formed (ca. 4.5 billion years ago).

Their results imply that the ingredients for life (water, carbon compounds, sulfur, etc.) were introduced later, likely by an impact.