Astronomers find most distant galaxy ever

This is a Hubble Space Telescope image of the farthest confirmed galaxy observed to date (inset). The near-infrared image of the galaxy (inset) has been colored blue as suggestive of its young, and hence very blue, stars.
NASA, ESA, P. Oesch and I. Momcheva (Yale University), and the 3D-HST and HUDF09/XDF Teams

Talk about a galaxy far, far away.

Using data from NASA's Hubble and Spitzer space telescopes and the Keck I 10-meter telescope at the W. M. Keck Observatory in Hawaii, an international team of astronomers, led by Yale University and University of California scientists, identified what they believe is the most distant galaxy ever measured.

"Every confirmation adds another piece to the puzzle of how the first generations of galaxies formed in the early universe," Pieter van Dokkum of Yale, a second author of the study, said. "Only the most sensitive telescopes are powerful enough to reach to these large distances."

Named EGS-zs8-1, the galaxy, astronomers believe, is one of the brightest and biggest objects in the early universe. The scientists say the galaxy formed between 400 million and 600 million years after the Big Bang, at a time when the universe was only 5 percent of its present age of 13.8 billion years.

The discovery shows the power of Hubble and the other telescopes to push the frontiers of space and builds on the identification of distant galaxies uncovered in 2013 and 2012.

"One of the most dramatic discoveries from Hubble and Spitzer in recent years is the unexpected number of these very bright galaxies at early times close to when the first galaxies formed," said Garth Illingworth, professor of astronomy and astrophysics at UC Santa Cruz and a co-author on the paper describing the discovery that appeared in The Astrophysical Journal Letters. "We still don't fully understand what they are and how they relate to the very numerous fainter galaxies."

Astronomers say the galaxy looks to be only 100 million years old, a time when it was forming its first stars.

Pascal Oesch, lead author of the study from Yale University, said the galaxy has already grown more than 15 percent of the mass of our own Milky Way today. It was also still forming stars, about 80 times faster than our Milky Way Galaxy.

Researchers said observations show EGS-zs8-1 at a time when the universe was undergoing very important changes: the hydrogen between galaxies was transitioning from an opaque to a transparent state.

"It appears that the young stars in the early galaxies like EGS-zs8-1 were the main drivers for this transition, called reionization," said study co-author, Rychard Bouwens of the Leiden Observatory, Leiden, Netherlands.

The discovery also confirmed that massive galaxies did exist early in the history of the universe, though their physical properties were very different than what we see in the sky today. Their colors, for one, indicate a very rapid formation of massive, young stars, which interacted with the primordial gas in these galaxies.

  • Michael Casey

    Michael Casey covers the environment, science and technology for