In the center of a galaxy far, far away (13 million light years to be exact) lives a black hole. At the center of the Circinus galaxy, this object has a mass millions of times that of the sun, so large that nothing can escape its pull, not even light. Research into this galaxy has resulted in huge achievement in physics — and possibly brought us a step closer to understanding black holes.
Almost every large galaxy we know of has a supermassive black hole at its center, even our own. In fact, the 2020 Nobel prize in physics was awarded to several physicists (including the 4th woman in history to win the prize for physics) who proved conclusively that there is a black hole at the center of our galaxy by observing the stars close to the center orbiting it. In 2019, this black hole was famously photographed; our first image of a black hole ever.
These black holes are often considered the ‘engines’ of galaxies. Particles, dust, and gas from the galaxy are drawn towards the center by the immense gravitational pull of the black hole. This matter begins to orbit the black hole, falling into the mass. This creates a kind of ‘disk’ of particles surrounding the black hole, which physicists refer to as the ‘accretion disk’. This disk is the common collection of stuff that you will see around a black hole in almost any artist’s rendering of what these celestial bodies look like. As the matter gets closer to the center, it begins to speed up, causing friction, and temperatures up to several million degrees. This creates what astrophysicists call an active galactic nucleus — which brightly emits more than most stars in the galaxy. When the black hole finally swallows the matter, it is turned into energy. This energy is then sent out back into the galaxy, which affects the formation of new planets, stars, and solar systems. Black holes are the most efficient system in nature when it comes to converting matter into energy: about 50%, which is several billion times more efficient than something like petrol.
Recent research from Tohoku University in Japan has made even more strides in the research of these accretion flows and the structure of a black hole itself. By taking high resolution measurements at the Atacama Large Millimeter/Submillimeter Array (ALMA) observatory, a massive array of radio telescopes in the Chilean desert, the group was able to actually capture the accretion flow heading into the black hole located at the center of the Circinus galaxy. By studying an area of the accretion disk, very close to the black hole that was several light years in length, the team was able to pinpoint exactly where the flow was heading into the active galactic nucleus. This discovery marks the first time this has been captured, and an important step to understanding the accretion mechanisms themselves.
Black holes have always been something of fascination for everyone: physicists to science fiction enthusiasts. Discoveries like this one represent a step forward to better understanding our universe — making science less a thing of fiction.
