Astronomers discover three distinct groups of merging black holes
Black hole collisions do not appear to come from one simple cosmic recipe. After studying more than 150…
Nearly invisible galaxy may be built mostly of dark matter, Hubble finds
A tight clump of four star clusters sits in the Perseus galaxy cluster, and at first glance it…
Gaia Detected an Entire Swarm of Black Holes Traveling Through The Milky Way
A fluffy cluster of stars spilling across the sky may have a secret hidden in its heart: a…