Associate Professor of Physics Dr. Lior Burko published a report on the stability of extreme black holes along with his colleague, Dr. Gaurav Khanna of the University of Massachusetts Dartmouth. The research demonstrates that extreme black holes can remain stable in spite of previously held notions.
“The previously thought instability is more a result of what class of observers you were looking at than the properties of space and time themselves,” Burko said.
According to Einstein’s theory of general relativity, there is a maximum rate of spin that a black hole of a certain mass can have. Black holes that spin at this maximum rate are known as “extreme” black holes.
“In many senses, extreme black holes behave differently than sub-extreme black holes,” Burko said. “It turns out that one of the ways they behave differently is how they respond to perturbations.”
A perturbation refers to mass that falls into the black hole, whether an asteroid or a cup of tea.
“Sub-extreme black holes radiate away all perturbations until they settle down to a quiescent state,” Burko said.
“It turns out that extreme black holes behave very differently, and when you perturb them a little bit, the perturbations don’t decay the same way. They actually grow in time, such that if you wait long enough, the perturbations become very large. This is what led people to suggest eight years ago that extreme black holes are unstable.”
The new research published by Burko and Khanna shows that this is not necessarily the case. Using sophisticated computer models developed by Khanna, the pair made the realization that an unstable picture of extreme black holes is specific to only one class of observer.
“If you look only at quantities that all classes of observers will agree on, then you see no instability at all,” Burko said. “Quantities that everyone agrees on all decay to zero, and we also found the rate at which they all decay to zero.”
hat this means for physics has yet to be defined. The paper is still new and has faced scrutiny from some members of the scientific community.
“They have their own arguments why they thought their conclusion was right and our conclusion was not. Other people accepted what we did and even started building on with it and used the results,” Burko said. “The paper has already been cited by a number of other papers.”
Burko came to GGC in 2014 after working as faculty at Bates College in Maine, the University of Alabama, and also in France. He received his doctorate degree from the Technion Israel Institute of Technology.
Burko spoke about his decision to teach at GGC.
“I really like the mission,” Burko said, “the fact that it is an access school. I think it’s a terrific mission.”
Burko also spoke about what makes GGC unique.
“GGC is not structured the way colleges have been the last hundred years,” Burko said. “Other institutions still work under the assumption that they are still getting the same type of students that they did in the 1950s, but that’s not true anymore. It’s not the same type of students, and therefore, we also don’t need to teach in the same way that people taught in the 1950s. In many places, they still do because they go by inertia.”