Are Comets Responsible for Earth’s Abundant Water Supply?
The findings suggest that comets may have delivered far more water than previously believed.
Some scientists suggest that repeated, cataclysmic collisions with comets may have played a significant role in depositing water on Earth, challenging earlier theories about its origins.
A reanalysis of data from the European Space Agency’s (ESA) Rosetta mission to the iconic “rubber ducky” comet has revived the idea that comets contributed a substantial amount of water to Earth.
The findings suggest that comets may have delivered far more water than previously believed.
Over the past decade, the hypothesis that comets were major contributors to Earth’s water had fallen out of favor.
However, new insights from the Rosetta mission, as reported by Live Science, are prompting scientists to reconsider.
Water is one of Earth’s most abundant molecules, with its oceans containing about a million trillion tonnes of it.
Despite its simple chemical composition—two hydrogen atoms and one oxygen atom per molecule—the question of how Earth acquired such an immense volume of water remains unresolved.
While some of Earth’s water may have originated from geological processes, many researchers argue that most of it likely arrived through repeated impacts from comets or asteroids during the planet’s early history.
These celestial bodies would have delivered water during violent collisions, seeding Earth with the liquid essential for life.
A key piece of evidence lies in Earth’s deuterium-to-hydrogen (D/H) ratio, which closely resembles that of many asteroids and some comets from the Jupiter-family.
These comets, characterized by their orbits influenced by Jupiter’s gravity, swing past the Sun approximately every 20 years.
The similarities in D/H ratios between Earth’s water and that of Jupiter-family comets support the notion that such comets contributed significantly to Earth’s water supply.
As scientists continue to analyze data from missions like Rosetta, our understanding of Earth’s watery origins may shift, reopening old debates and revealing new insights about the dynamic processes that shaped our planet.