Update 76, Origins of Earth’s Water

Origins of Earth's Water

New research has proposed a groundbreaking theory, suggesting that Earth might have formed much more rapidly than previously believed. Instead of the gradual accumulation of larger bodies over millions of years, the theory proposes that our planet was born from tiny millimeter-sized pebbles that rapidly aggregated within a few million years. Even more intriguing is the idea that Earth’s water, a vital ingredient for life, was not delivered by icy comets but was drawn from its surrounding space environment during its early years. This intriguing concept may have significant implications for the search for life beyond our solar system, hinting that watery and habitable planets around other stars could be more common than we currently theorize.

The new theory, presented by a team of researchers, revolves around the early stages of our solar system, approximately 4.5 billion years ago, when the young Sun was encircled by a proto-planetary disk composed of gas and dust. In this environment, dust particles swiftly accumulated to form planets once they reached a critical size. For Earth, this “vacuuming up” process, drawing in disk material, played a key role in supplying the planet with water.

Isaac Onyett, a Ph.D. student at the Centre for Star and Planet Formation, University of Copenhagen, elaborated on the process, stating, “The disk also contains many icy particles. As the vacuum cleaner effect draws in the dust, it also captures a portion of the ice. This process contributes to the presence of water during Earth’s formation, rather than relying on a chance event delivering water 100 million years later.”

The traditional theory of planet formation posits that planets gradually grow through the collision and merging of smaller bodies over an extended period. In this scenario, the presence of water on Earth would be attributed to a fortuitous event, such as a bombardment by icy comets towards the end stages of its formation. However, the new theory challenges this notion and diminishes the reliance on chance events.

The researchers used silicon isotopes as a metric to understand the mechanisms and timescales of planet formation. Analyzing the isotopic composition of over 60 meteorites and planetary bodies, they established a connection between Earth and other rocky planets in the solar system. This led them to theorize that whenever a planet like Earth forms, it is likely to have water.

Martin Bizzarro, a professor at the Globe Institute and a member of the team, explained, “This theory would predict that whenever you form a planet like Earth, you will have water on it. If you go to another planetary system where there is a planet orbiting a star the size of the sun, then the planet should have water if it is in the right distance.”

The implications of this theory are profound. It opens up the possibility of a more widespread distribution of watery and potentially habitable planets around other stars in the universe. The findings challenge the notion that Earth’s water came from a singular, chance event and instead point towards a more systematic process that could be applicable to exoplanets as well.

The research, described in a paper published in the journal Nature, represents a significant step forward in our understanding of planet formation and the prevalence of water in the cosmos. As we continue to explore the universe, this new theory encourages us to reevaluate our perspectives on the origins of Earth’s water and the likelihood of finding life on other distant worlds.


The findings were documented in a research paper published in the journal Nature on Wednesday, June 14th. Found here.