PASADENA, Calif., Dec. 13 (UPI) -- U.S. astronomers say they've discovered primitive galaxies formed more than 13 billion years ago, when the universe was less than 4 percent of its current age.
The Hubble Space Telescope, in its deepest images to date, has captured a robust sample of seven galaxies that tells how abundant they already were shortly after the era when galaxies first formed, a NASA release said Thursday.
A team of astronomers led by Richard Ellis of the California Institute of Technology in Pasadena used Hubble's Wide Field Camera 3 to peer deeper into space in near-infrared light than any previous Hubble observation.
The newly observed galaxies are seen as they looked 350 to 600 million years after the Big Bang, with their light just arriving at Earth now, they said.
Astronomers said the Hubble images have provided the first reliable census of this epoch.
A major goal of the study, scientists said, was to determine how rapidly the number of galaxies increases over time in the early universe, a measure that can provide key evidence for how quickly galaxies build up their constituent stars.