A ghostly ribbon of stars reveals hidden dark matter
Astronomers have discovered the first stellar stream outside the Milky Way, providing a new method to map dark matter distribution in other galaxies. By analyzing the gravitational influence on the stream's stars, researchers can better estimate the total mass of the host galaxy.
Why it matters
Advances our understanding of dark matter, a fundamental mystery in astrophysics that influences the structure of the universe.
For billions of years, an ancient cluster of stars has been gradually coming apart, shedding stars that now form a faint, narrow ribbon across space. That delicate structure is offering astronomers a new way to investigate one of the universe's biggest mysteries.
An international research team, including an astrophysicist from Northwestern University, has identified the first stellar stream of this type ever observed outside the Milky Way. Astronomers have long predicted that such streams should exist around other galaxies, but their extreme faintness has made them difficult to detect.
The newly discovered stream also offers scientists an unusual tool for studying dark matter, which remains one of the major unanswered questions in astrophysics. By analyzing the stream's shape, researchers reconstructed the gravitational field of its host galaxy and used that information to determine how unseen dark matter influenced the stars' paths.
Get smarter about the news
Sign up free for a feed built around what you actually care about, Dive Deeper research on any story, and the full text of every article.
Create free accountAlready have an account? Sign in