The first stars in the universe, huge behemoths thousands of times the mass of our sun, could have formed in the blink of an eye, cosmologically speaking, after the big bang.
The James Webb Space Telescope (JWST) has been able to detect distant galaxies from when the universe was . Models suggest star formation could have begun even earlier in the 13.8-billion-year history of the universe, perhaps within 200 million years or less.
and at Tohoku University in Japan think it could have been earlier – much earlier. By modelling star formation in the early universe, they found it might have been possible for huge stars up to 10,000 times the mass of our sun to have formed within 20 million years, or even as soon as 1 million years, after the big bang.
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“Our model says there are more density fluctuations in the [early] universe,” says Ito, meaning that matter might have more readily clumped into clouds of gas that could have collapsed into stars earlier than expected.
The first stars in our universe, known as Population III stars, were giant balls of mostly hydrogen. They have never been definitively detected, although there .
According to Ito, the first 20 million years of the universe would have seen higher temperatures caused by the cosmic microwave background – the remnant heat of the expansion of the universe. This would have made these stars much more massive than modern stars, up to 10,000 times the mass of our sun, because they would gather in gas more easily.
“As the accretion rate becomes larger, the stellar mass becomes larger,” says Ito, forming giant stars that would have existed for just a few million years before exhausting their fuel and exploding as supernovae.
at the University of Portsmouth in the UK thinks it is unlikely that matter would have clumped enough to form stars so early in the universe. “At this point [in the universe], there are density perturbations, but none of them are enough to form stars,” he says.
Whalen says it is possible that a “very rare” clump of gas could have coalesced in the first 40 million years of the universe, but the chances of ever detecting this are extremely slim. “You’d be very hard pressed,” he says.
JWST is probing further back into the universe than ever before, but it is still limited by the amount of infrared light it can collect. at the Rochester Institute of Technology in New York says that while it is unclear what the limit of the telescope is, it is probably around 200 million years after the big bang. “We could potentially see supernovae at earlier times if we get lucky,” she says. “But we’d have to look in the right place at the right time.”
If star formation did begin much earlier than this, it is unlikely we will know that for the time being. “It’s not possible for JWST,” says Ito. “But maybe the next generations of telescopes.”
arXiv
