Star light. Star bright. First star

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By Roger Snodgrass

Not long after the beginning, as cosmologists currently explain it, some of the first and largest stars the universe has ever known ended their lives in the most powerful thermonuclear explosions in all of nature.

“What we really want to find, is literally the first supernovae,” said Daniel Holz, a cosmologist and member of a team of exploratory researchers at Los Alamos National Laboratory who are pursuing “the First Cosmic Explosions.”

There are many reasons to want to find representatives of this first population of stars.

Because they are the first, Holz said, “They are made of just the stuff that came out of the big bang.”

As a link in the narrative of how we ended up being here, he added, “This is the stuff that kicks it off.”

The ancestral stars his group is searching for were hundreds of times bigger and consisted of only primordial matter, hydrogen and helium atoms, according to current simulations of when the universe was only 1 percent of its current age.

That was a few hundred million years after the great expansion, when the universe was an infant.

The laboratory’s project builds on earlier theory and efforts to find indirect evidence that these stars existed and proposes “a method by which direct detection may be possible.”

“The very first question is can we see them,” said Holz, referring to objects that are as close to the edge of the universe as we can observe.

In order to answer that question, he added, we need to know how bright they are and how often they happen, findings the team will derive from simulations of first generation stars.

“If they don’t happen often enough, we won’t be able to see them,” Holtz said.”

One hopeful technique for seeing so far back in time and so distantly across the cosmos is called “gravitational lensing,” a phenomenon by which light is bent by gravitational effects as it passes through the material influences universe. In some instances the light source can become magnified by as much as a hundred times. Up until now, most lensing studies have focused on much nearer objects.

After the researchers have refined new estimates and possibilities, they may be able to feed that knowledge into forthcoming space and astronomical missions that could be programmed and equipped to deliver something that might once have seemed impossible, a direct observation of “the death throes of one of the very first stars in the universe.”

Other members of the team include Alexander Heger at the University of Minnesota, Bruce Fryxell and Daniel Whalen at LANL, Candace Church at the University of Southern California, and Brian O’Shea at Michigan State.