In Search of the First Stars

In Search of the First Stars

Recent observations narrow one long-standing gap in big bang cosmology—a component of RTB’s creation model—by gaining understanding of the formation of the universe’s first stars.

The scientific enterprise exists to explain the world in which we live. Models provide the framework for building and testing those explanations. While any legitimate model must explain the relevant phenomena, predictions of future discoveries make the model worth investigating. That’s why Reasons To Believe emphasizes the need for Christians to develop testable models if they want to bring their ideas into the scientific arena. The very nature of predictions means that a model contains “gaps” that haven’t been filled or validated by experiments/observations.

Big bang cosmology argues that the universe started fourteen billion years ago in a hot, dense state. As the universe expanded and cooled, a number of transformations led up to the introduction of human life. Three minutes after the creation event, the only elements in the universe, practically speaking, were hydrogen and helium. One critical transformation involved the generation of significant quantities of more massive elements. Stars provided the mechanism for generating these elements.

As astronomers sought to understand how stars could produce the observed distribution of elements in the universe, they realized that several different kinds of stars contributed to this development. Population III stars form a key link in the series of stars leading up to the formation of Sun-like stars. However, these Population III stars likely experienced a fleeting existence. Because of their massive nature, they consumed fuel rapidly and burned out in less than a million years. Yet they seeded future stars with elements beyond helium. These second generation stars were typically much smaller and burned for much longer.

Recent observations may have produced the first direct detection of an immediate offspring of Population III stars; it’s been given the catalog name BD+44o493. A key criterion for finding these particular stars is a very low amount of iron. Astronomers have found just over a dozen such stars. BD+44o493’s abundance of other elements makes it stand out. First, it has an excess of carbon, which could’ve been produced by incorporating the remains of Population III stars as they exploded at the end of their lives. But it also could’ve resulted from other more mundane processes, such as the star extracting carbon from a binary companion or by forming near another type of dying star (the kind that formed later in the universe’s history) called an asymptotic giant branch star.

The group of astronomers used the abundances of other elements, such as oxygen and nitrogen, in BD+44o493, to see if they could distinguish between the possible formation mechanisms. They determined that a faint supernova, characteristic of Population III stars’ origin, was the best explanation for BD+44o493.

By generating elements more massive than helium, Population III stars began the critical process of making life’s building blocks. The research on BD+44o493 represents the next best thing to finding an actual Population III star: finding its offspring. Reasons To Believe anticipates more finds like this in the future and expects them to provide additional evidence for a cosmic Designer who fashioned the universe to support life.