Simulation of galaxy formation showing streams of gas feeding the growing galaxy.
Simulation created by Ceverino, Dekel, and Primack, courtesy UC, Santa Cruz.Scientists locate primordial gas clouds from just after creation of universe
November 13, 2011
(NATIONAL) -- We live in days of amazement and wonder as evidenced by what scientists have now found after a very long search.
For the first time, astronomers have found pristine clouds of the primordial gas that was formed in the first few moments after the “Big Bang," the event that created our universe, according to a report published the University of California, Santa Cruz.
By “first moments” astronomers mean, in this case, some 2 billion years after the big bang, or nearly 12 billion years ago.
And the composition of the gas they located matches theoretical predictions, which in turn provides 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. Then 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 - wherever they have looked in the universe.
"As hard as we've tried to find pristine material in the universe, we have failed until now. This is the first time we've observed pristine gas uncontaminated by heavier elements from stars," said J. Xavier Prochaska, professor of astronomy and astrophysics at the University of California, Santa Cruz.
Prochaska is coauthor of a paper on the findings published online in Science on November 10.
First author Michele Fumagalli is a UC Santa Cruz graduate student, and coauthor John O'Meara is at Saint Michael's College, Vermont.
"The lack of metals tells us this gas is pristine," 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."
The researchers discovered the two clouds of pristine gas by analyzing the light from distant quasars. They used a spectrometer on the Keck I Telescope at the W. M. Keck Observatory in Hawaii.
Powerful telescopes see distant objects as they were far back in time, due to the time it takes light to travel across the universe. The spectrographic analysis of the pristine gas clouds places them in time at about 2 billion years after the Big Bang.
At that time, theoretical models predict that galaxies were growing by pulling in vast streams of cold gas, but these "cold flows" have never been seen.
According to Fumagalli, the pristine gas clouds are potential candidates for these elusive cold flows. Further studies are needed, however, to see if the newly discovered gas clouds are associated with galaxies.