Comets may have been responsible for the presence of water on Earth, scientists claim, according to a new study published this week in Scientific progress. The researchers focused on comet 67P/Churyumov-Gerasimenko and found that the molecular structure of water on the celestial body was very similar to that of Earth's oceans. While water existed in the form of gas and dust when Earth formed about 4.6 billion years ago, scientists have raised questions about how it eventually became rich in liquid water.
Researchers believe that a significant portion of our oceans comes from the ice and minerals on asteroids and possibly comets that crashed into Earth. To further develop their theory, the researchers led by Kathleen Mandt, a planetary scientist at NASA's Goddard Space Flight Center, decided to use an advanced statistical calculation technique to determine the molecular structure of water on 67P, which belongs to the Jupiter family of comets. should be found. captured by the European Space Agency's (ESA) Rosetta mission to the asteroid.
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The specific signature of the Earth
Earth's water has a unique molecular signature related to specific rations of the hydrogen variety, or isotope, called deuterium. In recent decades, deuterium levels in water found in the vapor trails of several Jupiter family comets have shown levels similar to those of Earth's water.
“So I was just curious if we could find evidence that this happened at 67P. And this is just one of those very rare cases where you propose a hypothesis and actually see it happen,” Ms. Mandt said.
As it turned out, Ms. Mandt's team found a clear link between deuterium measurements in the comet and the amount of dust around the Rosetta spacecraft.
'As a comet moves closer to the Sun in its orbit, its surface heats up, releasing gas from the surface, including dust with bits of water ice on it. Water with deuterium adheres to dust grains more easily than plain water,” the study points out.
“If the ice on these dust grains goes into coma, this effect could make the comet appear to have more deuterium than it does,” it added.
The research has major implications not only for understanding the role of comets in providing water to Earth, but also for understanding cometary observations that provide insights into the formation of the early solar system.
