First Extragalactic Globular Cluster Stream Reveals Dark Matter Distribution

Astronomers have discovered a faint ribbon of stars— a globular cluster stellar stream— orbiting a distant galaxy, marking the first such stream identified beyond the Milky Way. The stream’s stars trace the galaxy’s gravitational field, allowing researchers to map the amount and distribution of the surrounding invisible dark matter. By studying how the stream’s stars move, scientists can infer the shape and density of the galaxy’s dark matter halo. This new method provides a powerful tool for probing dark matter in other galaxies, potentially shedding light on one of the universe’s most enduring mysteries.