A team of 10 Chinese astronomers recently announced the first-ever discovery of a supermassive black hole binary.1 They found the binary in the galaxy NGC 5548 (see figure 1), a galaxy where more than 70 percent of its light comes from the nuclear core. Previous research teams had determined that a supermassive black hole with a mass 280 million times the sun’s mass resided in the nuclear core.2
Details on the First-Detected Supermassive Black Hole Binary
The team found a 14-year periodicity in the double-peaked profile of the hydrogen-beta spectral line and in the brightness of both the hydrogen-beta emission line and the optical continuum arising from the nuclear core. These periodicities imply that the “supermassive black hole” is really two black holes of roughly equal mass that orbit one another with a separation of 21.7 light-days or 350 billion miles. This separation is approximately 100 times the distance between Neptune and the sun.
Figure 1: Seyfert galaxy NGC 5548
Image credit: NASA/ESA Hubble Space Telescope
Further confirmation for a supermassive black hole binary residing in the galactic center of NGC 5548 comes from a very deep exposure image of NGC 5548. This image shows two long tidal tails, indicating that NGC 5548 is the product of two roughly equal mass galaxies that merged about 1 billion years ago. Each of the two galaxies that merged to become NGC 5548 would have contained a supermassive black hole at their respective galactic centers. A billion years is a reasonable time for the orbit of the two supermassive black holes around one another to decay to a distance of about 22 light-days.
NGC 5548 is 244 million light-years away from Earth. It is a little more than five times closer to us than the merger of two 30-solar-mass black holes discovered by the Laser Interferometer Gravitational-Wave Observatory (LIGO). NGC 5548’s proximity to Earth and the very high mass of its black hole binary make it an excellent target for detecting gravitational waves.
Eventually, the two supermassive black holes in NGC 5548’s center will merge. That merger will impact the LIGO instrument with gravitational waves billions of times stronger than those detected from the merger of the two 30-solar-mass black holes. However, it will probably be at least another million years before the merger of NGC 5548’s supermassive black holes occurs. Nevertheless, NGC 5548’s supermassive black holes are already close enough together to radiate detectable gravitational waves.
How Is the Creation Model Affected?
In their paper, the team calls for the search of additional supermassive black hole binaries. Additional supermassive black hole binaries will not only aid research on the properties of gravity and general relativity but also assist in testing cosmic creation models. The predominant big bang creation model predicts that galaxy merger events were common in the early history of the universe. While many images of galaxy merging events have been collected, a comprehensive catalog of the characteristics of supermassive black hole binaries in galaxies would yield truly definitive tests of the leading big bang creation models.
The recent discovery of gravitational waves emanating from the merger of two 30-solar-mass black holes (and the potential discovery of more medium-sized black hole merger events) has been significant in the defense of the biblically predicted big bang creation model. This discovery illuminates a core feature of the creation model by providing a much more detailed understanding of the universe’s firstborn stars and of the subsequent star formation history of the universe. However, presently operating gravity wave telescopes are reliant upon rare merger events (either two medium-sized black holes within a few billion light-years from Earth, or two small black holes or neutron stars in a nearby galaxy) to generate a signal strong enough to detect gravitational waves. Even then, the detectable gravitational signal lasts only a few seconds. But the discovery of a different kind of black hole binary—a supermassive black hole binary—promises to augment scientists’ ability to study gravitational waves.
With access to gravitational waves emanating from both medium-sized and supermassive black hole binaries, astronomers will be able explore new properties of gravity and general relativity. They will be able to gain a greater understanding of the universe’s star and galaxy formation history and, consequently, of the cosmic creation event and development of the universe. This deeper understanding may help remove some of the remaining doubts about the validity of the biblically predicted big bang creation model.3