Scientists have discovered an extremely old "iron poor" star in the Milky Way galaxy, 35,000 light-years from earth and one of the first members of the second generation of stars born after the big bang 13.8 billion years ago, according to a new report published in the monthly notices of the royal astronomical society, a leading international astronomical journal.

The red giant, named SMSS j160540.18-144323.1, is estimated to have the lowest iron content of any galaxy star analyzed by humans, meaning it is the oldest known star in the universe.

Thomas nordland, an astronomer at the Australian national university's center for astrophysics, said the star appears to be so starved of iron that if its mass were to be considered an Olympic swimming pool, it would contain only one drop of iron.

The metal content is a reliable indicator of when a star formed. Because there was so little metal in the infant universe, a star's unusually low iron content suggests that it is a very old body.

The sun or the 100th generation of stars born after the big bang, based on metal content. The previous record for ultra-low iron content was about 11,750 times that of the sun. But the newly discovered stars have only 1.5 millionths as much iron as the sun.

Since the big bang, the "first generation" of stars have been short-lived, so they have only been seen in theory. The stars are thought to be the first members of the second generation. It, too, is on the verge of death and will soon run out of hydrogen for a helium fusion reaction, but its appearance could improve understanding of the universe's earliest moments.