Universe's first star born tiny and grew huge

This matter was generally very smoothly distributed throughout the universe, but some regions had greater concentrations of it than others, the researchers said.

The effects of the gravity from this matter drew in more and more material over time, setting in motion clouds of hydrogen and helium that came together as a "protostar" -- the seed of a much larger star.

The first protostar was born about 300 million years after the Big Bang, the researchers said. Nuclear reactions inside the protostar made it the first object to cast starlight in what some astronomers call the "cosmic dark ages," they added.

It was a relatively tiny object at first, 1 percent the mass of the sun. But within about 10,000 years -- "the blink of an eye," according to the researchers -- it grew into a giant full-fledged star at least 100 times the sun's mass.

While none of the stars survive today, their influence remains.

The processes churning inside the stars synthesized the universe's first heavy elements. In dying, these stars may have blasted this stuff back into space to become building blocks of future stars and planets composed of many more elements.

Hernquist said these stars may have died in a very bright supernova or might have collapsed in on themselves, forming black holes with relatively little of their material ejected into space as ingredients for future stars.

(Editing by Maggie Fox and Sandra Maler)