Scientists simulate early cosmos, find gigantic stars

The stimulation stops there, but additional calculations suggest that within 1,000 years, the proto-star would have grown into a star 10 times more massive than the sun. By 10,000 years, the star would have topped 100 times the sun's mass.

Such huge stars are thought to have lived only for about 1 million years, compared with an expected lifetime of roughly 10 billion years for the sun.

The new results are important, says Tom Abel, a researcher at the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University who published his own group's simulations in 2002. They confirm his team's results, which showed that these first stars probably grew in isolation from each other, and that they don't fragment along the way, as some have suggested.

But the new work also traces the formation of the first stable proto-stars. No star could form without these stable proto-stars, even in today's universe, Dr. Hernquist says.

New tools to see more stars

Now, cosmologists who focus on theory have their work cut out for them, Dr. Abel says in an e-mail. "We know exactly what happens until the first stars are one-hundredth the mass of the sun. We know they will attain approximately 100 times the solar value."

The task is to provide accurate pictures of what goes on in between, while a star's mass is burgeoning by a factor of 10,000, he adds. This will require far more complex programming and more computer horsepower.

Meanwhile, astronomers are pressing existing tools into action to try to push back the veil on the dark ages, notes Elizabeth Barton, an astronomer at the University of California at Irvine. For instance, astronomers have reported the discovery of large galaxies when the universe was roughly 780 million years old. Some tantalizing but disputed evidence has emerged for galaxies or galaxy-wannabes some 300 million years earlier.

Studies of second or third-generation stars will help, many of which may be orbiting in the halo of the Milky Way galaxy.

Astronomers in the US and China are also building an enormous radiotelescope array consisting of about 10,000 antennas in China's Xinjiang Province. They plan to use it to map the first glowing "bubbles" that appear as radiation from galaxies begins to ionize the dense fog of hydrogen between them and light it up.

"The only way we're ever going to understand this is when the theoretical work that's progressing rapidly in this field meets up with the observations work, which is coming from the other direction" of the timeline, says Dr. Barton.

"It's a big puzzle," she adds, and the new results, which appear in Friday's edition of the journal Science, represent a small but important piece.

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