New study tracks chemical elements in space rocks
A team of scientists has unveiled groundbreaking findings suggesting that meteorites likely brought the building blocks of life to Earth. These space travelers, fractured remnants of early asteroids, may have delivered the essential chemicals that eventually led to the emergence of life.
Tracing Earth’s volatile elements
The research focused on tracking the origins of Earth’s “volatiles,” chemicals that are critical to life. Volatiles include water and other key elements. The scientists specifically studied zinc, a chemical found in meteorites, which holds clues to the origins of these essential compounds.
“One of the most fundamental questions on the origin of life is where the materials we need for life to evolve came from,” said Rayssa Martins, lead author of the study from the Department of Earth Sciences at the University of Cambridge. “If we can understand how these materials came to be on Earth, it might give us clues to how life originated here and how it might emerge elsewhere.”
The role of planetesimals
The study reveals that the meteorites that brought these life-essential elements to Earth were once part of planetesimals, the small rocky bodies that are considered the building blocks of planets. These planetesimals formed around 4.6 billion years ago in the protoplanetary disk surrounding the young Sun.
Some planetesimals formed early and were exposed to intense radiation from the infant Sun, causing them to lose their volatiles through vaporization. Others, formed later, retained much of their volatile content. The research shows that these “unmelted” planetesimals, which did not experience as much radiation, played a significant role in delivering volatiles to Earth.
Zinc’s cosmic journey
By studying zinc in meteorites, the researchers discovered that nearly half of the zinc on Earth originated from the inner regions of the solar system, while the rest likely came from beyond Jupiter. Remarkably, although melted planetesimals account for 70% of Earth’s mass, they contributed only 10% of its zinc. The remaining 90% came from unmelted planetesimals, which are thought to have delivered a large portion of the planet’s volatiles.
This finding suggests that these unmelted space rocks carried crucial ingredients for life, potentially answering the long-standing question of how Earth received the materials necessary for life to evolve.
A key to understanding life beyond Earth?
The discovery has major implications for understanding the origins of life not only on Earth but also elsewhere in the universe. Martins and her team hope that further research into these early solar system materials will offer insights into how life might emerge on other planets.
“If we can piece together how life’s building blocks arrived on Earth, we can begin to understand the processes that could make life possible elsewhere,” Martins concluded.
This study represents a significant step forward in unraveling the mysteries of how life began, potentially opening new avenues for exploring extraterrestrial life.