Plenty of water may have existed in space in first billion years after Big Bang

A new study has revealed that plenty of water may have existed in space in the first billion years after the Big Bang.

The early universe lacked elements heavier than hydrogen and helium. The first generation of stars was believed to have been massive and short-lived. Those stars generated elements like oxygen, which then spread outward via stellar winds and supernova explosions. This resulted in "islands" of gas enriched in heavy elements. Even these islands, however, were much poorer in oxygen than gas within the Milky Way today.

The team examined the chemical reactions that could lead to the formation of water within the oxygen-poor environment of early molecular clouds. They found that at temperatures around 80 degrees Fahrenheit, abundant water could form in the gas phase despite the relative lack of raw materials.

Although ultraviolet light from stars would break apart water molecules, after hundreds of millions of years equilibrium could be reached between water formation and destruction. The team found that equilibrium to be similar to levels of water vapor seen in the local universe.

This current work calculated how much water could exist in the gas phase within molecular clouds that will form later generations of stars and planets. It doesn't address how much water would exist in ice form (which dominates within our galaxy) or what fraction of all the water might actually be incorporated into newly forming planetary systems.