Illustration of two black holes merging, of comparable mass to what LIGO first saw. At the centers of some galaxies, supermassive binary black holes may exist, creating a signal far stronger than this illustration shows.(SXS, the Simulating eXtreme Spacetimes (SXS) project (http://www.black-holes.org))

Meet The Universe’s First-Ever Supermassive Binary Black Holes

If you thought LIGO’s recent discoveries were profound and unusual, wait until you meet OJ 287.

Recently, LIGO has revolutionized our knowledge of the Universe by discovering merging black holes.

The gravitational wave signal from the first pair of detected, merging black holes from the LIGO collaboration. The raw data and the theoretical templates are incredible in how well they match up. (B. P. Abbott et al. (LIGO Scientific Collaboration and Virgo Collaboration))

Near the centers of galaxies, mergers, accretion, and collisions create supermassive black holes undetectable by LIGO.

The sensitivities of a variety of gravitational wave detectors, old, new, and proposed. Note, in particular, Advanced LIGO (in orange), LISA (in dark blue), and BBO (in light blue). LIGO can only detect low-mass and short-period events; longer-baseline observatories are needed for more massive black holes. (Minglei Tong, Class.Quant.Grav. 29 (2012) 155006)

Practically all galaxies contain them, including our Milky Way.

This artist’s impression shows the orbits of stars around the supermassive black hole at the centre of the Milky Way. In 2018 one of these stars, S0–2, will pass very close to the black hole, presenting the best opportunity to study the effects of very strong gravity on its light and orbit. The orbits have been so well studied that we have directly determined the black hole’s mass to be four million solar masses. (ESO / L. Calçada)

When supermassive black holes feed on matter, they form active galactic nuclei or quasars.

An ultra-distant quasar showing plenty of evidence for a supermassive black hole at its center. How that black hole got so massive so quickly is a topic of contentious scientific debate, but mergers of smaller black holes formed in early generations of stars might create the necessary seeds. (X-ray: NASA/CXC/Univ of Michigan/R.C.Reis et al; Optical: NASA/STScI)