Is Earth's water older than the Sun?

Could water have been one of the planet-forming materials in the Solar System? Ilsedore Cleeves, an astrochemist at the University of Michigan in Ann Arbor, conducted a study wherein she created a model that replicates the conditions in the universe when the Sun was born to predict how much of water on Earth was formed before the Sun’s birth. She calculated the effect of the radiation released by the young Sun and the outer space on the Solar System and how far the radiation traveled. This helped to study the formation of new water molecules from oxygen and hydrogen and whether they had deuterium, an isotope of hydrogen that is present in abundance in interstellar clouds where new stars like the Sun are born. The research team found lower levels of deuterium-containing water in the water present in the Solar System in comparison to its estimated amount in star-forming atmospheres. Cleeves and her team thus concluded that up to 50% of water on Earth must have existed before the Sun was formed.   

Read more in Nature.