by Ashis Sinha
A new study published in Science Advances this week proposes that comets may have played a key role in bringing water to Earth. Scientists focused on Comet 67P/Churyumov-Gerasimenko and found that the molecular structure of water on this celestial body closely resembles that of Earth’s oceans. This discovery could help explain how Earth, which formed around 4.6 billion years ago, became rich in liquid water.
The researchers, led by NASA’s Kathleen Mandt, believe that a significant portion of Earth’s oceans may have originated from the ice and minerals found on comets and asteroids that collided with our planet. To investigate this theory, the team used advanced statistical techniques to analyze the molecular structure of water on 67P, using data collected by the European Space Agency’s Rosetta mission.
A crucial aspect of this research revolves around deuterium, a variant of hydrogen, which gives water its unique molecular signature. Over recent decades, scientists observed that deuterium levels in water found in the vapor trails of several Jupiter-family comets were similar to the levels found in Earth’s water. Mandt’s team was able to confirm these findings when they discovered a clear connection between the comet’s deuterium levels and the amount of dust surrounding the Rosetta spacecraft.
“When a comet moves closer to the Sun, its surface warms up, releasing gas and dust that contains water ice,” explained Mandt. “Water with deuterium adheres more strongly to dust grains than regular water, which could explain why the comet appeared to have more deuterium than it actually did.”
This study offers a new perspective on the origins of Earth’s water and suggests that cometary impacts may have played a significant role in shaping the planet’s water-rich environment.
