Water on Earth is even older than our Sun

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile have discovered gaseous water present in the disk surrounding the star V883 Orionis, where planets are formed. The chemical composition of this water provides insight into the process through which water travels from star-forming gas clouds to planets. This discovery strengthens the theory that water on Earth existed even before our Sun.

John J. Tobin, an astronomer at the National Radio Astronomy Observatory, USA and lead author of the study published in the journal Nature, and his team used the ALMA observatory, an array of radio telescopes in northern Chile, to observe the gaseous water in V883 Orionis and found this disc contains at least 1200 times the amount of water in all of Earth's oceans.

Tobin and colleagues examined a variant of water that contains deuterium, a heavy isotope of hydrogen, instead of one of the hydrogen atoms (water is composed of one oxygen atom and two hydrogen atoms). As simple and heavy water form under different conditions, their ratio can be employed to track the time and location of water formation. For example, the ratio in some comets in the Solar System is similar to that found in water on Earth, implying that comets may have transported water to our planet.

Although the journey of water from clouds to young stars, and then later from comets to planets, has been witnessed in the past, the association between young stars and comets was missing until now, according to the researchers.

"V883 Orionis is the missing link in this case. The composition of the water in the disc is very similar to that of comets in our own Solar System. This is confirmation of the idea that the water in planetary systems formed billions of years ago, before the Sun, in interstellar space, and has been inherited by both comets and Earth, relatively unchanged," Tobin said.

2/ Astronomers have detected gaseous water in the planet-forming disc around the star V883 Orionis. This water carries a chemical signature that explains the journey of water & supports the idea that water on Earth is even older than our Sun 😮 Zoom in to V883 Orionis 👇 pic.twitter.com/qF85HcwXCT

— ESO (@ESO) March 8, 2023