Astronomers have penetrated another layer into the past, fishing out a galaxy believed to be formed just 500 million years after the birth of the universe.
"We're really pushing the envelope, so how prevalent these are there's a fair degree of uncertainty," astronomer Rychard Bouwens, with the University of California, Santa Cruz, and Leiden University, The Netherlands, told Discovery News.
If confirmed, the discovery would push back the appearance of galaxies about 100 million years closer to the Big Bang explosion, traceable from microwave background radiation, which occurred about 13.7 billion years ago.
"It's plausible," astronomer Naveen Reddy, with the National Optical Astronomy Observatory in Tucson, Ariz., told Discovery News. "I wouldn't bet my house on it, but I may bet my lunch."
The galaxy, known as UDFj-39546284, was found in near-infrared images taken by the Hubble Space Telescope in 2009 and 2010.
Light from the galaxy produces a distinctive pattern as it passes through gases lying between it and the telescope, which orbits around Earth to avoid interference from our atmosphere. Variations in the chemical fingerprints can be used to calculate distance, much like the way the sound of train whistle changes in measurable degrees as shifts toward or away from us.
The celestial yardstick is called "redshift," since light stretches to longer wavelengths, toward the color red on the electromagnetic spectrum, as it travels over greater distances. The newly discovered galaxy has a redshift of about 10.3, which means its light has traveled about 13.2 billion years to reach us. Light travels at a constant speed of 186,000 miles per second.
"Looking for objects at redshift 10 is extremely painstaking process," Bouwens said. "Essentially what we're looking at here is the tip of the iceberg."
The detection of even one galaxy at this distance tells scientists that there wasn't as much star formation going on in the oldest galaxies as there was in galaxies appearing just 100 million years later, though the object could be a fluke.
"Ideally, you'd like to be able to probe large areas of the sky," Reddy said. "Some parts may be over dense, or under dense, with respect to the true average of the universe."
Finding even older galaxies likely will have to wait until Hubble's successor, the James Webb Space Telescope, is launched. NASA is trying to figure out how to make up a $1.5-billion cost overrun in the $5-billion program and get the new telescope launched as early as 2015.
Bouwen's research appears in this week's Nature.