In the past, scientists believed water molecules could not have existed until the first star was formed, but new research suggests water vapor may have existed in pockets of space only a billion years after the Big Bang.
Scientists previously believed oxygen had to disperse and link up with hydrogen in large amounts in order to create water, but this new research suggests it may have been around earlier than we thought after all, the Harvard-Smith Smithsonian Center for Astrophysics reported.
"We looked at the chemistry within young molecular clouds containing a thousand times less oxygen than our Sun. To our surprise, we found we can get as much water vapor as we see in our own galaxy," said astrophysicist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA).
The early universe did not contain elements heavier than hydrogen and helium, but early stars are believed to have generated elements such as oxygen that was spread through stellar winds, creating "islands" of gas-enriched heavy elements. Despite this phenomenon, the element islands were most likely much poorer in oxygen than what is seen in the Milky Way today.
The research team looked at chemical reactions that could potentially lead to water formation within these oxygen-poor environments of early molecular clouds. They determined that at temperatures of around 80 degrees Fahrenheit, abundant water could be created in the gas phase.
"These temperatures are likely because the universe then was warmer than today and the gas was unable to cool effectively," said lead author and PhD student Shmuel Bialy of Tel Aviv University.
"The glow of the cosmic microwave background was hotter, and gas densities were higher," added Amiel Sternberg, a co-author from Tel Aviv University.
The ultraviolet light emitted by the early stars would have broken apart the water molecules, but after hundreds of millions of years water formation and destruction could have balanced each other out and reach similar water levels to what is seen in the local universe.
"You can build up significant quantities of water in the gas phase even without much enrichment in heavy elements," Bialy said.
The findings were published in a recent edition of the Astrophysical Journal Letters.
