The First Stars

Astronomers hope to soon spot the universe's earliest stellar inhabitants

- BY JOSÉ MARÍA DIEGO RODRÍGUEZ

The primordial galaxy known as the Sunburst Arc appears four times in this image from the Hubble Space Telescope. The light from the galaxy, which lies 11 billion light-years away, has been distorted and magnified into curving smudges by the mass of the galaxy cluster in the center of the image. One of the oldest known stars, Godzilla (circled), is visible within this galaxy.

ON CHRISTMAS DAY 2021, alongside other astronomers, I watched the James Webb Space Telescope (JWST) launch from French Guiana and begin its month-long journey to its destination, 1.5 million kilometers from Earth. The trip was filled with many nerve-racking moments, particularly the week-long period in which the telescope's tennis-court-size sun shield array slowly unfolded like origami from its bus-size liftoff configuration.

Luckily, JWST made the trip safely and began operations in the summer of 2022. Since then, the observatory has started answering some of the biggest questions in astronomy. It's also raised many new ones.

One of the biggest surprises that has emerged is the discovery that supermassive black holes, some with masses more than a million times that of the sun, existed when the universe was no more than about 3 percent of its current age. How such massive black holes came to exist so long ago is a puzzle. Perhaps less massive black holes formed from the explosive deaths of the first stars, known as Population III stars, and those black holes later merged under the influence of gravity to form a million-solar-mass black hole.

But how could thousands of these smaller black holes have combined in the cosmically short period of hundreds of millions of years? To figure it out, we need to understand the very first stars, which, to date, no one has ever seen individually.