GALAXY WITHOUT DARK MATTER
Astronomers have become confident that most of the matter in the universe is made of a shadowy substance called dark matter. It is the glue that binds galaxies together. Another way to think of it is as the scaffold on which the universe’s construction projects are built. So it was shocking to find a galaxy seemingly devoid of it earlier this year. Known as NGC 1052-DF2, its lack of dark matter was discovered using the Dragonfly Telephoto Array in New Mexico.
The team behind the discovery studied ten star clusters orbiting close to the galaxy. They were travelling far slower than expected, suggesting there’s scant gravitational pull from local dark matter to accelerate them to high speeds. The job now is to figure out how the 10-billion-year-old galaxy formed without it. Some are calling it the impossible galaxy. It could turn out to be a blow for an alternative theory to dark matter: modified gravity. Advocates for the theory say gravity works differently at different scales. Yet that would affect all galaxies equally. The fact this one is missing dark matter suggests the shadowy substance is really out there, just not here.
observations of NGC 1052-DF2show lack of dark matter