Local physics prof talks black holes and the expanding universe
By William Crooks
Local Journalism Initiative
In a July 29 interview, Valerio Faraoni, a professor of theoretical physics at Bishop’s University, shared exciting developments in his research on black holes, furthering our understanding of these mysterious cosmic objects and their relationship with the expanding universe. Faraoni delved into the intricacies of his recent findings and their potential implications for cosmology.
Faraoni began by highlighting a recent collaboration with a colleague from Italy, culminating in a paper published just last week. This paper explores black holes in the context of an expanding universe, a topic that has intrigued scientists for decades. “The masses of black holes at the centres of galaxies increase with the expansion of the universe,” Faraoni said, summarizing his findings. This observation ties into a larger question about how black holes evolve as the universe itself expands and accelerates.
Black holes are found in various contexts within the universe. There are stellar mass black holes, with masses comparable to that of the sun, and supermassive black holes at the centres of galaxies. Faraoni noted that we have extensive observational evidence for these black holes, including gravitational waves and radio pictures of regions near black hole horizons. “This is not speculative stuff. This is pretty much established,” he emphasized.
To explain further, a stellar mass black hole is formed when a massive star collapses under its own gravity after exhausting its nuclear fuel. These black holes typically have a mass several times that of our sun. On the other hand, supermassive black holes reside at the centres of galaxies and can have masses ranging from millions to billions of times that of the sun. Gravitational waves are ripples in space-time caused by violent astrophysical processes, such as the collision of black holes. The horizon of a black hole, or event horizon, is the boundary beyond which nothing, not even light, can escape the gravitational pull of the black hole.
