A region of the Andromeda galaxy, as imaged by Hubble’s Panchromatic Hubble Andromeda Treasury, along with the unusual, X-ray emitting object J0045+41, now known to be an ultra-distant binary supermassive black hole. Image credit: NASA/CXC/University of Washington/ESA.

The Largest Black Hole Merger Of All-Time Is Coming, And Soon

Sometimes, you look in a nearby galaxy, and what you find beyond it will change everything.

Einstein’s theory of General Relativity has withstood every test for more than a century.

The General Relativity picture of curved spacetime, where matter and energy determine how orbiting, inspiraling systems evolve over time, has made successful predictions that no other theory can match. Ripples in spacetime can be generated by fast orbiting stars (neutron stars, white dwarfs or black holes). Image credit: NASA.

From the bending of starlight to orbital decay, Einstein’s predictions for spacetime’s behavior have never failed.

As two neutron stars orbit each other, Einstein’s theory of general relativity predicts orbital decay, and the emission of gravitational radiation. In the final stages of a merger — never before observed in gravitational waves — the amplitude should spike so high that LIGO could, conceivably, detect them. Image credit: NASA (L), Max Planck Institute for Radio Astronomy / Michael Kramer.

Since 2015, the final stages of black hole and neutron star inspirals and mergers have been observed directly.

With numerous black hole-black hole mergers under its belt and even a neutron star-neutron star collision, gravitational wave astronomy has blossomed into a bona fide science over the past two years. Image credit: LIGO-Virgo/Frank Elavsky/Northwestern University.

The holy grail of black hole mergers, however, would be an inspiraling system that we could monitor consistently throughout the decay process, culminating in a merger.