'Delivered by a Comet': Scientists suggest that Earth's water came from beyond our Solar System

Produced by: Tarun Mishra

Key Insight into Earth's  Water Origins

A recent study led by NASA’s Goddard Space Flight Center investigates the potential role of comets in delivering water to early Earth. The findings focus on Comet 67P/Churyumov–Gerasimenko, suggesting its water closely resembles that found in Earth's oceans.

Revisiting the Debate on Cometary Contributions

The study, led by Kathleen Mandt and published in Science Advances, reignites the debate over whether Jupiter-family comets like 67P played a significant role in supplying Earth’s water during its early history.

Challenges of Water  Retention on Early Earth

Water is vital for life, but Earth's early proximity to the Sun likely caused much of its original water to vaporize. This gap may have been filled by icy bodies like comets and asteroids during heavy bombardment 4 billion years ago.

Findings from ESA's  Rosetta Mission

Earlier studies from ESA’s Rosetta mission suggested 67P’s water had high deuterium levels, a heavy hydrogen isotope, appearing incompatible with Earth's water composition.

Credit: ESA

Advances in Measurement Techniques

Mandt's team reanalyzed over 16,000 water measurements from Rosetta, discovering that dust from 67P’s surface affected deuterium readings. They identified a direct correlation between dust levels and isotope measurements, challenging prior conclusions.

Implications for Solar  System Formation

The study underscores the importance of accounting for dust effects in cometary analysis. These findings not only refine our understanding of 67P’s water composition but also offer new insights into the formation processes of the solar system.

Cometary Water’s Role  in Supporting Life

If future studies confirm the link between cometary and terrestrial water, this could reshape theories about how life-sustaining resources were delivered to Earth, potentially highlighting comets' critical role.

Future Directions  for Research

Mandt emphasizes the need for updated methodologies in analyzing cometary water and preparing for future missions. Understanding the relationship between comets and Earth's water could provide answers about the origins of life on our planet.