Have Astronomers Found Evidence Of The Universe's First Stars?

Scientists have long-theorized that in the earliest days of the universe, space was dominated by enormous stars hundreds of times more massive than the Sun, and there might finally evidence to prove they existed. In concert with the newest data about the oldest galaxies from the James Webb Space Telescope, astronomers have more information about the origins of the universe than ever before. When humans gaze into the night sky the field of stars may appear uniform, but there is a wealth of diversity among them.

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Our Sun, a G-type yellow-dwarf main sequence star, boasts a core that fuses hydrogen into helium, which will burn for billions of years to come. But our Sun will eventually evolve, as all stars do, changing form over its lifespan. When our Sun runs out of hydrogen and then helium, it will expand so significantly that it will swallow its innermost planets in turn, including Earth. It will transition from a yellow-dwarf star into a red giant, then a white dwarf, and then it will eventually fade into oblivion. This process, already complex, is still the life-cycle of but one type of star, and is indicative of how much there is to know about the myriad types of stars populating the universe. The older a star type is, the more it can reveal about the universe’s origins, but the more challenging it is to find reliable data.

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Now, new research published in the Astrophysical Journal contends that scientists have identified traces of the explosive death of one of the universe’s first stars. Although approximations are constantly evolving, scientists currently estimate that the universe is 13.7 billion years old. Primordial stars are believed to have begun forming when the universe was still young, which in this context means perhaps only 100 million years old, but concrete evidence of those stars has been hard to come by. An innovative new method for studying quasars — distant, young galaxies that proliferate in the outer reaches of the observable universe — has led to the discovery of a distinctive chemical signature that may be the first conclusive evidence of the earliest stellar giants.

We Are All Made Of Star Stuff, Literally

Artist's impression of Population III starfield
Credit: NOIRLab/NSF/AURA/J. da Silva/Spaceengine

The first stars, known as Population III, were so massive that their short lives ended in pair-instability supernovae, a specific type of eruption that sends the entirety of a star’s makeup scattering across space without leaving behind a black hole, neutron star, or other classic marker of more conventional supernovae. Because the earliest stars were so completely decimated, astronomers must be particularly meticulous detectives when searching for them, scouring the universe for subtle chemical fingerprints.

Confirming this discovery will require experts to replicate the findings. In a press release, co-author Timothy Beers, an astronomer at the University of Notre Dame, noted that next steps include examining space closer to home for evidence of similar chemical traces. “We now know what to look for; we have a pathway,” he said.If this happened locally in the very early Universe, which it should have done, then we would expect to find evidence for it.” If such evidence is discovered, the scientific understanding of the universe’s origins will be rendered in unprecedented detail. This study’s observations were made using NSF’s NOIRLab Gemini North earth-based telescope, and astronomers can hope to learn even more by pointing the James Webb Space Telescope that way soon.

As Carl Sagan famously said, “We’re all made of star stuff.” Our bodies are made up of matter, and while that matter has been in existence for billions of years, it had to have come from somewhere. It is partly because of this that the origins of the universe is such a subject of fascination. If this discovery is confirmed, it stands to clarify our understandings of how that early matter formed in space, and how it evolved into the universe we know today, with us in it.

Source: Astrophysical Journal, EurekAlert!

2022-09-30T20:05:25.000Z

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