Black hole collisions evade detection
Search for gravitational waves from galactic cores turns up empty
![black hole](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/09/092215_cc_black-hole_free.jpg?fit=860%2C460&ssl=1)
MAKING WAVES As supermassive black holes spiral together, they should radiate gravitational waves (illustrated) — spacetime ripples that have yet to be directly detected.
Swinburne Astronomy Productions