Scientists find earliest galaxy
Believed to be from 13.2 billion years ago
An international team of astronomers say they have glimpsed the earliest galaxy yet, a smudge of light from nearly 13.2 billion years ago —a time when the cosmos was a far lonelier place.
The research has not been confirmed, and some astronomers are skeptical. The new findings are based on an image from the Hubble Space Telescope and are published in Thursday's issue of the journal Nature. The scientists calculate the galaxy dates to just 480 million years after the Big Bang.
That would trump last year's announcement by a French team who said they found a galaxy from about 600 million years after the Big Bang. That discovery also is not universally accepted and one of the skeptics is the co-author of the latest paper.
Even more interesting than the advanced age of the newly discovered galaxy is the absence of other similarly aged bright galaxies. That indicates that star formation during that point in the universe's early childhood was happening at a rate 10 times slower than it was millions of years later, said study co-author Garth Illingworth of the University of California Santa Cruz.
Astronomer Rychard Bouwens talks about the discovery on Quirks & Quarks on Jan. 29 at noon on CBC Radio One.
Illingworth described what the cosmos might look like at that time period when the universe was smaller and the stars bluer and dimmer.
"It wouldn't be nearly as interesting — a blob here, a blob there," he said in a phone interview.
But other astronomers have their doubts about this discovery.
Richard Ellis at the California Institute of Technology is troubled because Illingworth's team originally found three 13.2 billion-year-old galaxies and then withdrew their original study.
The authors then came up with an entirely different galaxy, so all that switching "makes it difficult to believe," he said.
Illingworth said originally he and colleagues confused what may have been real light from billions of years ago and background "noise" from the process of looking so far away, so they re-did the study. He said they then found the new galaxy and saw that it was more likely to be real than the previous ones.
"We made a mistake and luckily we had ways to catch it before we went out and it was formally published," said Illingworth, whose co-authors included astronomers from the Netherlands and Switzerland.
Ellis and Henry Ferguson of the Space Telescope Science Institute said they were also worried that the Illingworth team only used one of several telescope filters to find this galaxy. They speculated that they might have found an object that's much nearer.
Illingworth acknowledged in his paper that there is a 20 per cent chance that the smudge they found is contamination, but "we're pretty sure it's a real object."
Ferguson said Illingworth did "a very good job of making that detection convincing."
The vaunted 20-year-old Hubble telescope has progressively produced images of older and more distant objects. Peering earlier into space will require the more advanced cameras of NASA's new James Webb Space Telescope, Illingworth said. However, it isn't likely to launch until at least 2015.
The farther away a galaxy, the longer it takes for light from it to travel, so seeing the most distant galaxies is like looking back in time. If the new research were correct, light from the newly found galaxy would have travelled 13.2 billion light years to be seen by Hubble.