Scientists using NASA’s James Webb Space Telescope stumbled upon a surprising discovery – a dwarf galaxy named PEARLSDG that challenges existing knowledge of galaxy formation. This unexpected find occurred during a study of a galaxy cluster, showcasing the telescope’s capabilities beyond its initial research objectives.
Dwarf galaxies, characterized by their relatively small size, typically contain around a thousand to a few billion stars, making them less bright and harder to detect than larger galaxies like the Milky Way. These galaxies are either quiescent, interacting with larger galaxies, or isolated, forming new stars on their own, according to conventional scientific understanding.
However, PEARLSDG breaks this mold. Located 98 million light years away from Earth, this dwarf galaxy doesn’t fit the expected profile. Unlike other dwarfs, PEARLSDG isn’t forming new stars, and it isn’t interacting with a larger galaxy. This led scientists to propose that it might be a rare example of an isolated quiescent dwarf galaxy.
The discovery challenges current theories of galaxy evolution, as isolated quiescent dwarf galaxies were not considered likely to exist. Tim Carleton, the study leader from the University of Arizona, explained that generally, dwarf galaxies on their own continue to form new stars.
Using the James Webb Space Telescope’s instruments, scientists examined specific stars within PEARLSDG and found that they lacked the color signature associated with new stars. This indicated not only a lack of new star formation but also that the existing stars in the galaxy are relatively old.
While PEARLSDG may be a unique case, scientists believe it could represent one of many isolated quiescent dwarf galaxies awaiting discovery. The unexpected find highlights the telescope’s potential to unveil previously unknown aspects of our universe.