Water found on Earth could be older than the Sun, suggesting life may exist on distant exoplanets.
Researchers showed how water is "inherited" by the environment when a star is born; if this is true other exoplanetary systems may have also had access to the same life force, the University of Exeter reported.
"This is an important step forward in our quest to find out if life exists on other planets. We know that water is vital for the evolution of life on Earth, but it was possible that the Earth's water originated in the specific conditions of the early solar system, and that those circumstances might occur infrequently elsewhere," said Professor Tim Harries, from the University of Exeter's Physics and Astronomy department
To make their findings the researchers looked at the composition of comets and asteroids, which revealed ices were circling the Sun at the time of its birth.
"By identifying the ancient heritage of Earth's water, we can see that the way in which our solar system was formed will not be unique, and that exoplanets will form in environments with abundant water. Consequently, it raises the possibility that some exoplanets could house the right conditions, and water resources, for life to evolve," Harris said.
The researchers used "heavy water" ice (made from deuterium rather than hydrogen) to determine at which point water ices formed in the creation of our solar system. The team used an advanced modeling technique to show excess heavy water came from a pre-Sun environment
"There has been a long-standing question as to whether any of these ancient ices, including water, are incorporated into young planetary systems, or if all the preplanetary building blocks are reprocessed and/or locally synthesized near the star," said Ilsedore Cleeves, a PhD student at the University of Michigan and lead author on the paper.
In the first scenario, all planetary systems would grow from similar seed materials such as interstellar water; alternatively the chemical make-up of planets would be dependent on what type of star they were hosted by.
"The implication of these findings is that some of the solar system's water must have been inherited from the Sun's birth environment, and thus predate the Sun itself. If our solar system's formation was typical, this implies that water is a common ingredient during the formation of all planetary systems," Cleeves said.
The findings were published Sept. 26 in the journal Science.
