Scientists Crack the Code, Unveil Origins of Life Seeds on Earth

How did life begin on Earth? This enduring question has fascinated scientists for years, and a recent study offers a new perspective, suggesting that meteorites may have played a key role in bringing the essential components for life to our planet.

According to the study, meteorites likely delivered the building blocks of life to early Earth from space. This discovery has piqued scientists’ interest, as it implies that extraterrestrial life could exist somewhere in the universe.

The research focuses on meteorites, which are believed to be the fragmented remains of early “unmelted asteroids.” These small rocky bodies, known as planetesimals, are considered the primary building blocks of planets in our solar system. They formed around 4.6 billion years ago from the dust and gas surrounding the young sun. As particles swirled around the star, they began to clump together, gaining mass and eventually forming larger bodies.

A team of scientists set out to investigate the origin of Earth’s “volatiles” by tracking the chemical element zinc in meteorites. Volatiles, which include six common chemicals crucial for life—such as water—are essential for the evolution of life.

Rayssa Martins, the lead author of the study from the Department of Earth Sciences at the University of Cambridge, explained, “One of the most fundamental questions about the origin of life is where the necessary materials came from.” She added, “If we can understand how these materials arrived on Earth, it might give us clues about how life started here and how it could develop elsewhere.”

 

The Role of Zinc

The researchers, including teams from Cambridge and Imperial College London, focused on zinc because its unique composition in meteorites can reveal information about the origins of volatiles. Previous findings suggested that Earth’s zinc came from various parts of the solar system—approximately half from the inner solar system and the rest from regions beyond Jupiter.

There are different types of planetesimals. The earliest ones, formed during the solar system’s infancy, were exposed to intense radiation from the young sun. As a result, they lost many volatiles due to vaporization. Later planetesimals, however, were not subjected to as much radiation, allowing them to retain most of their volatiles.

By studying zinc in meteorites from various planetesimals, the researchers traced how zinc arrived on Earth over millions of years. They discovered that while melted planetesimals contributed to about 70% of Earth’s total mass, they only accounted for around 10% of its zinc. The remaining 90% of Earth’s zinc likely came from “unmelted” planetesimals.

The team concludes that these unmelted meteorites may have also brought significant amounts of other volatiles to early Earth, helping to create the conditions necessary for life.