Black hole collisions evade detection
Search for gravitational waves from galactic cores turns up empty
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
Supermassive black hole duos are awfully quiet. Searches for spacetime ripples radiating away from these spiraling monsters are coming up empty, a new study reports. The silence is providing hints of the complex interactions at play in the final stage of galaxy collisions.
When galaxies collide, the gargantuan black holes in their cores sidle up to one another. As the two spiral together over billions of years, they radiate gravitational waves. Efforts to detect the cacophony of waves from black hole couples throughout the universe should be turning something up by now. New observations, however, indicate that this “gravitational wave background” is quieter than most theories predict, Ryan Shannon, an astronomer at CSIRO Astronomy and Space Science in Marsfield, Australia, and colleagues report.
The new data, from 11 years of pulsar observations and reported in the Sept. 25 Science, sharply disagree with most calculations of just how loud this
