The first stars may not have been as uniformly massive as we thought

For decades, astronomers have wondered what the very first stars in the universe were like. These stars formed new chemical elements, which enriched the universe and allowed the next generations of stars to form the first planets.

The first stars were initially composed of pure hydrogen and helium, and they were massive—hundreds to thousands of times the mass of the Sun and millions of times more luminous. Their short lives ended in enormous explosions called supernovae , so they had neither the time nor the raw materials to form planets, and they should no longer exist for astronomers to observe.

At least that’s what we thought.

Two studies published in the first half of 2025 suggest that collapsing gas clouds in the early universe may have formed lower-mass stars as well. One stud