Hubble's new finds go the distance: galaxies discovered nearly 13.1 billion light-years from Earth.

Just days after NASA released the first cosmic dreamscapes taken by the newly refurbished Hubble Space Telescope (SN: 9/26/09, p. 7), three teams of astronomers have used the observatory to find what appears to be a bounty of the most distant galaxies known.

Analyses of infrared images captured in August and September with the newly installed Wide Field Camera 3 suggest there were fewer bright galaxies early in cosmic history and those galaxies formed stars at an unexpectedly low rate.

Because they do not yet have measurements of the individual wavelengths that make up the galaxies' spectra, the teams do not directly know how far away the galaxies lie. But the starlit bodies' colors suggest that about 16 reside roughly 12.9 billion light-years from Earth and another five or so sit around 13.06 billion light-years away, a record-breaking distance.

"We are looking back 13 billion years and seeing galaxies just 600 to 700 million years after the Big Bang, when the universe was like a 4-year-old," says Garth Illingworth of the University of California, Santa Cruz, a member of one of the discovery teams.

The new camera's greater sensitivity and its larger field of view have enabled scientists to rapidly find what appear to be extremely remote galaxies, says Richard Ellis of Caltech in Pasadena, a coauthor of two of four papers that the three teams recently posted at arXiv.org.

"This is a golden moment," Ellis says. "All the groups independently analyzed the data with different software and broadly speaking, we're all in agreement."

The researchers find a marked downturn in the number of bright galaxies as the telescope peers farther away and thus further back in time. That decrease in the galactic population is expected from current models of galaxy formation, says Harry Ferguson of the Space Telescope Science Institute in Baltimore, who was not a member of any of the teams.

The findings "appear to show that galaxy formation is just starting at these [early times]," comments Simon White of the Max Planck Institute for Astrophysics in Garching, Germany.

Because the investigated area is tiny and because the Wide Field Camera 3 has only just begun taking pictures, it is difficult to know how representative the findings are of the rest of the universe at that time, Ferguson and Ellis caution.

Ellis notes that the new findings also hint at a puzzle. His team estimates that the distant galaxies, which are too tiny to be clearly resolved by Hubble, are making stars at a puny rate. In some cases, that rate is as low as the mass equivalent of 0.0025 suns per year. According to current models, that rate couldn't have generated enough ultraviolet starlight for a critical milestone in the evolution of the universe--the wrenching apart of neutral hydrogen atoms into their subatomic constituents.

This is not yet an astronomical crisis, Ellis says. The first stars may have produced more ultraviolet radiation than expected. Or ultraviolet light may have more easily escaped the early galaxies.

New data that may solve this and other cosmic riddles are just starting to pour in, Ellis says. "This is a very exciting time."