Astronomers Discover Oldest Stars in Universe

The massive blue stars were observed in a number of young and very bright galaxies, including one dubbed CR7--a nod to the Portuguese soccer player Cristiano Ronaldo.

"The discovery challenged our expectations from the start, as we didn't expect to find such a bright galaxy," Dr. David Sobral, an astrophysicist at the University of Lisbon in Portugal and leader of the team of astronomers who made the discovery, said in a written statement. "Then, by unveiling the nature of CR7 piece by piece, we understood that not only had we found by far the most luminous distant galaxy, but also started to realize that it had every single characteristic expected of Population III stars."

Population III stars are those that formed from the primordial material left over after the Big Bang--the light elements hydrogen, helium, and lithium. (Our sun is classified as a Population I star, meaning that it's of relatively recent origin and contains heavier elements.)

Population III stars had long been believed to exist but had never been seen until now.

"This field, of first-generation stars and galaxies, was mostly theoretical until recently," Dr. Avi Loeb, chair of Harvard University's astronomy department, told Science magazine. "It's gratifying to see evidence that these are real things."

Scientists have been eager to learn more about these early stars in part because they are believed to have forged all the heavier elements that make up our bodies and our world.

The stars were discovered using observations made with the European Southern Observatory's Very Large Telescope in northern Chile, as well as the W.M. Keck Observatory and the Subaru Telescope in Hawaii, and the Hubble Space Telescope.

A paper describing the research was accepted for publication in The Astrophysical Journal.