WASHINGTON -- Astronomers believe they've found the oldest thing they've ever seen in the universe: It's a galaxy far, far away from a time long, long ago.
Hidden in a Hubble Space Telescope photo released earlier this year is a small smudge of light that European astronomers now calculate is a galaxy from 13.1 billion years ago. That's a time when the universe was very young, just shy of 600 million years old. That would make it the earliest and most distant galaxy seen so far.
By now the galaxy is so ancient it probably doesn't exist in its earlier form and has already merged into bigger neighbors, said Matthew Lehnert of the Paris Observatory, lead author of the study published online Wednesday in the journal Nature.
"We're looking at the universe when it was a 20th of its current age," said California Institute of Technology astronomy professor Richard Ellis, who wasn't part of the discovery team. "In human terms, we're looking at a 4-year-old boy in the life span of an adult."
While Ellis finds the basis for the study "pretty good," there have been other claims about the age of distant space objects that have not held up to scrutiny. And some experts have questions about this one. But even the skeptics praised the study as important and interesting.
The European astronomers calculated the age after 16 hours of observations from a telescope in Chile that looked at light signatures of cooling hydrogen gas.
Earlier this year, astronomers had made a general estimate of 600 to 800 million years after the Big Bang for the most distant fuzzy points of light in the Hubble photograph, which was presented at an astronomy meeting back in January.
In the new study, researchers focused on a single galaxy in their analysis of hydrogen's light signature, further pinpointing the age. Garth Illingworth of the University of California, Santa Cruz, who was the scientist behind the Hubble image, said it provides confirmation for the age using a different method, something he called amazing "for such faint objects."