Oldest galaxy so far is found
Light from object is 13.1b years old
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 yesterday 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. “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 estimates of the age of distant space objects that have not held up to scrutiny. And some specialists 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 million 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 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.
What’s most interesting to astronomers is that this finding fits with theories about when the first stars and galaxies were born. This galaxy would have formed not too soon after them.
“We’re looking almost to the edge, almost within 100 million years of seeing the very first objects,’’ Ellis said. “One hundred million years to a human seems an awful long time, but in astronomical time periods, that’s nothing compared to the life of the stars.’’