Researchers at the University of California, Santa Cruz, said the composition of the gas matches theoretical predictions, providing direct evidence in support of the modern cosmological explanation for the origins of elements in the universe.
Only the lightest elements, mostly hydrogen and helium, were created in the big bang, and a few hundred million years passed before clumps of this primordial gas condensed to form the first stars, where heavier elements were forged.
Until now, astronomers have always detected "metals" -- their term for all elements heavier than hydrogen and helium -- everywhere they have looked in the universe.
"As hard as we've tried to find pristine material in the universe, we have failed until now," J. Xavier Prochaska, professor of astronomy and astrophysics, said in a UC Santa Cruz release Thursday. "This is the first time we've observed pristine gas uncontaminated by heavier elements from stars."
The researchers discovered the two clouds of pristine gas using the HIRES spectrometer on the Keck I Telescope at the W.M. Keck Observatory in Hawaii.
"The lack of metals tells us this gas is pristine," researcher Michele Fumagalli said. "It's quite exciting, because it's the first evidence that fully matches the composition of the primordial gas predicted by the big-bang theory."