Hidden star factories in early universe found.

• Position: Outer Space

Some of the brightest galaxies in the universe--infant galaxies that churned out tens of thousands of stars each year at the dawn of the universe--evolved much sooner and in greater numbers than previously thought, according to new measurements obtained by astronomers. The research is the most recent example of the discoveries coming from the international ALMA observatory, which stands for Atacama Large Millimeter/submillimeter Array--66 radio telescopes located in the dry and cloudless Atacama Desert in Chile.

The most intense bursts of star birth are thought to have occurred in the early universe, in massive, bright galaxies. These starburst galaxies used to convert vast reservoirs of cosmic gas and dust into new stars at a furious pace--many hundreds of times faster than in stately spiral galaxies like our own Milky Way. By looking far into space, at galaxies so distant that their light has taken many billions of years to reach us, astronomers can observe this busy period in the universe's youth.

"Even though these galaxies are among the brightest objects in the universe, they are very hard to see with telescopes that detect visible light, such as the Hubble Space Telescope," explains Dan Marrone, assistant professor at the University of Arizona's Steward Observatory. The reason is that these young galaxies are enshrouded in thick clouds of dust. "Instead, we use ALMA to look for them in light coming from the dust itself. To ALMA, these are some of the brightest objects in the sky outside our own galaxy."

The researchers first discovered these distant and enigmatic starburst galaxies with the National Science Foundation's 10-meter South Pole Telescope and then used ALMA to zoom in on them to explore the stellar baby boom in the young universe. They were surprised to find that many of these...