The recent discovery of two supermassive black holes orbiting each other has sent shockwaves through the scientific community, marking a significant milestone in our understanding of the universe. This groundbreaking observation, made possible by the RadioAstron satellite and the Event Horizon Telescope, opens up a new era in black hole physics and astrophysics. While the so-called "Golden Age" of black hole research spanned from Roy Kerr's 1963 solution to Stephen Hawking's 1973 revelation of black hole evaporation, this new development takes us to the next level of exploration.
One of the most intriguing aspects of this discovery is the quasar OJ287, a blazar located 3.5 billion light-years away in the constellation Cancer. OJ287 hosts one of the most massive black holes ever observed, with a mass approximately 18 billion times that of our sun. But what makes OJ287 truly unique is the presence of a second, supermassive black hole orbiting at close range. This secondary black hole, with a mass of around 150 million solar masses, completes an orbit around the primary black hole in just 12 years, tilted above the main accretion disk.
The smaller black hole's orbit is a marvel of general relativity, as it precesses just like Mercury's path around the Sun. Every time it passes through the accretion disk, it triggers a dramatic outburst, quadrupling the quasar's brightness for 48 hours. This phenomenon has been observed since at least the 1900s, and it's a testament to the power of nature.
The discovery of OJ287 and its orbiting black hole is a result of the RadioAstron satellite, launched from the Baikonur Cosmodrome in Kazakhstan. RadioAstron, with its 10-meter-diameter radio telescope, made it possible to perform aperture synthesis with ground-based telescopes, creating a virtual telescope with a "dish" that could span thousands of kilometers. This technique, called interferometry, achieved a resolution a thousand times sharper than Hubble's in visible light.
The image of the two black holes, captured by RadioAstron, is a remarkable achievement. It was made possible by a system of radio telescopes, including the RadioAstron satellite, which was operational ten years ago when OJ287 was imaged. The satellite's radio antenna was halfway to the Moon at the time, which greatly improved the resolution. In recent years, we've only been able to use ground-based telescopes, which have lower resolution.
This discovery raises a deeper question: what does it mean for our understanding of the universe? It suggests that there's more to black holes than we initially thought, and it opens up new avenues for research. It also highlights the importance of international collaboration, as the analysis of OJ287's images involved researchers from around the world, including the University of Turku in Finland.
In my opinion, this discovery is a testament to the power of human curiosity and the importance of pushing the boundaries of scientific exploration. It's a reminder that there's still so much to learn about the universe, and it inspires me to continue exploring the wonders of the cosmos. As we continue to uncover the secrets of black holes, we may just find ourselves on the brink of a new scientific revolution.
