Water has been present in the universe since 100-200 million years after the Big Bang, scientists have discovered.
The study, published in the journal Nature Astronomy, suggests that the discovery means that habitable planets could have started forming billions of years earlier than previously thought and before the first galaxies had even formed.
Dr Daniel Whalen, from the University of Portsmouth’s Institute of Cosmology and Gravitation, who led the study, said that it was the first time that water had been modelled in the primordial universe.
According to the simulations used for the research, water molecules began forming shortly after the first supernova explosions, known as Population III (Pop III) supernovae.
These were essential for the creation of heavy elements such as oxygen which are required for water to exist.
Dr Whalen said: “Before the first stars exploded, there was no water in the universe because there was no oxygen. Only very simple nuclei survived the Big Bang – hydrogen, helium, lithium and trace amounts of barium and boron.
“Oxygen, forged in the hearts of these supernovae, combined with hydrogen to form water, paving the way for the creation of the essential elements needed for life.”
Dr Whalen explained that the team, which included scientists from the United Arab Emirates University, examined two types of supernovae.
These were core-collapse supernovae, which produce a modest amount of heavy elements, and the “more energetic” Pop III supernovae, which eject tens of solar masses of metals into space.
The study found that both types of supernovae formed dense clumps of gas enriched with water.
Dr Whalen said that although the amounts of water produced was “modest” it was highly concentrated in cloud cores – dense regions of gas – which were believed to be the birthplaces of stars and planets.
He added: “The key finding is that primordial supernovae formed water in the universe that predated the first galaxies. So water was already a key constituent of the first galaxies.
“This implies the conditions necessary for the formation of life were in place way earlier than we ever imagined – it’s a significant step forward in our understanding of the early universe.
“Although the total water masses were modest, they were highly concentrated in the only structures capable of forming stars and planets. And that suggests that planetary discs rich in water could form at cosmic dawn, before even the first galaxies.”