Water on Earth found to be billions of years older than previously thought, may be older than our Sun

Observing the gaseous water turned out to be tricky, as most of the water in planet-forming discs is frozen out as ice, making it hidden from view. However, the V883 Orionis disc was shown in a recent study to be unusually hot, and a dramatic outburst of energy from the star heats the disc, "up to a temperature where water is no longer in the form of ice, but gas, enabling us to detect it," said lead author John J. Tobin, an astronomer at the National Radio Astronomy Observatory in the US.

The discovery is significant because the journey of water from clouds to young stars, and then later from comets to planets, has previously been observed, but until now the link between the young stars and comets was missing.

"V883 Orionis is the missing link in this case," said Tobin. "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."

The team's observations and findings demonstrate the sensitivity and ability of ALMA to detect and determine the composition of gaseous water, as well as map its distribution within the disc.

The detection of water in the V883 Orionis disc provides new insights into the origins of water in our Solar System and supports the theory that water on Earth is older than our Sun.