For the first time, scientists have recreated the universe’s very first molecules by simulating conditions from the early universe. This groundbreaking research, published on July 24 in the journal Astronomy and Astrophysics, is changing how we think about the origins of stars.
Right after the Big Bang occurred 13.8 billion years ago, the universe was extremely hot. But within seconds, it cooled enough for hydrogen and helium to form—the two first elements. Eventually, atoms combined with electrons, creating molecules in this cooler environment.
One key discovery from this study is the helium hydride ion, known as HeH+. This molecule was the first ever created and is critical for forming molecular hydrogen, which is the most abundant molecule we see today. These molecules played a crucial role in the formation of the first stars hundreds of millions of years later.
For a star to begin the fusion process, which allows it to generate energy, its atoms and molecules need to collide. This typically happens at temperatures above 18,000 degrees Fahrenheit (10,000 degrees Celsius). However, helium hydride ions can promote this process even in cooler conditions, making them vital for early star formation.
The researchers believe that the abundance of helium hydride ions in the early universe significantly influenced how quickly and effectively stars formed. They conducted experiments by cooling these ions to nearly absolute zero—minus 449 degrees Fahrenheit (minus 267 degrees Celsius)—and observed how well these ions interacted with heavy hydrogen. Surprisingly, even at lower temperatures, reaction rates didn’t decrease, contradicting previous beliefs.
Holger Kreckel, a nuclear physicist involved in the research, explained, “Older theories suggested that reactions would slow down significantly at low temperatures. Our findings challenge this notion.” This insight may alter our understanding of the chemical landscape in the early universe.
These research results emphasize that helium hydride ions were much more critical to chemistry in the early universe than previously thought. As scientists continue to uncover the complexities of our cosmos, each discovery brings fresh perspectives on how stars began to shine in the vast darkness of space.
The implications of this work are vast, hinting at new avenues for inquiry into astrophysics. With ongoing studies and technological advancements, our grasp of the universe’s beginnings continues to deepen.
