Some of the universe's earliest stars are too distant to see, but whether their fiery cores are fueled by dark matter could be determined by the glow surrounding them, scientists say.
If this elusive matter does power these stars, current infrared telescopes should be able to spot the resulting light, and the light signatures would differ from those of stars, like our sun, that rely on fusion.
Dark matter has never been detected directly and can be studied only by its gravitational effects on visible bodies. But its dominating presence – it is thought to compose 96 percent of the universe – could have played a significant role in the creation of the first stars, researchers say.
These dark-matter-powered stars, or dark stars, shine brightly regardless of their name. And although the individual starlight would be too distant to measure, astronomers can learn much from looking at the combined light of the universe's earliest stars, including those powered by dark matter. [Infographic Gallery: The History and Structure of the Universe]
"Since it is not possible to study star formation in the early universe directly, one relies on the results of numerical simulations," Andreas Maurer and Martin Raue, of the University of Hamburg in Germany, told SPACE.com in an email.
The researchers' findings appear in the February issue of the Astrophysical Journal.
As clouds of hydrogen and helium — the only two elements present in the early universe — collapsed, dark matter caught in the middle would be compressed.
Dark matter, just like regular matter, is thought to have a strange sibling called antimatter. "Every particle in the universe has an antiparticle," explained University of Chicago astrophysicist Douglas Spolyar, who was not involved in the new research, but who has studied how dark matter may have fueled early stars.
"This additional pressure 'blows up' the star, thereby reducing nuclear fusion," the researchers said.
"Given a sufficient supply of dark matter, dark stars can also have lifetimes exceeding the age of the universe — they could still exist today," Maurer said.
"The dark matter densities can be billions of times higher at the center of the galaxy, where stars can capture much more dark matter," Spolyar said. "Dark stars might be lurking at the center of the galaxy."
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