Class Note 1973
Issue
November-December 2024
Another year slips away….
The essay “Singularity or Structure?” by Yuan Ha received an honorable mention in the 2024 Gravity Research Foundation Essay Competition. Yuan condensed (below) the original essay for classmates.
“Black holes are now real astrophysical bodies after a hundred years of scientific debate about their existence. They are objects of such powerful gravity that even light cannot escape from their surface. Many supermassive black holes have been found at centers of galaxies where they play an important role in galaxy formation and star evolution. Without stars, there is no life in the universe.
“A dominant view of black holes in the last 60 years is known as singularity in which all matter falling into a black hole is crushed into a point with infinite density. The singularity has no size and zero volume. Matter is simply crushed out of existence. While this sounds absolutely mind-boggling and sensational, it is scientifically repugnant. Many physicists do not believe this. They have tried to resolve this problem but without success.
“Over time, the singularity concept has become an established dogma. People just let it be.
“But a Man of Dartmouth would not let it be. He worked on this mystery for 50 years and the answer emerged eventually from his senior fellow thesis. Here is the secret.
“Black holes are rotating bodies. A rotating body has a rotational inertia which keeps it rotating at a steady rate. If one tries to speed up or slow down its rotation, one must apply a tangential force in order to do so. A singularity does not have a rotational inertia because it is a point.
“The rotational inertia also determines the structure of a body. Take an ordinary example. Two eggs have the same size, shape, and weight. They are indistinguishable. However, one egg is a raw egg and the other one hard-boiled. Now rotation will tell them apart. The hard-boiled egg rotates easily while the raw egg rotates sluggishly. They have different rotational inertia and internal structure. For black holes, Man of Dartmouth found that every black hole has a rotational inertia showing it has a structure. There is an effective radius which is the radius of gyration known in mechanics.
“So what is the significance if black holes have a structure? Is it that important for astrophysics? The significance is scientific because the theorem that proclaims the singularity was recognized for the Nobel Prize in 2020. However, the black hole structure contradicts the singularity. We notice that major progress and paradigm shift in a given field occurs once every 50 years and this has been the case in science for several hundred years. A paradigm shift for black holes is inevitable. A notable example of a paradigm shift is the continental drift theory which contradicts the previous immovable continent dogma. The dogma was vigorously defended by the then leading authorities in geophysics for decades until it finally faded away.”
An exuberant Yuan may be contacted at yha@ccp.edu.
—Val Armento, 227 Sylvan Ave., San Mateo, CA 94403; valerie.j.armento.73@dartmouth.edu
The essay “Singularity or Structure?” by Yuan Ha received an honorable mention in the 2024 Gravity Research Foundation Essay Competition. Yuan condensed (below) the original essay for classmates.
“Black holes are now real astrophysical bodies after a hundred years of scientific debate about their existence. They are objects of such powerful gravity that even light cannot escape from their surface. Many supermassive black holes have been found at centers of galaxies where they play an important role in galaxy formation and star evolution. Without stars, there is no life in the universe.
“A dominant view of black holes in the last 60 years is known as singularity in which all matter falling into a black hole is crushed into a point with infinite density. The singularity has no size and zero volume. Matter is simply crushed out of existence. While this sounds absolutely mind-boggling and sensational, it is scientifically repugnant. Many physicists do not believe this. They have tried to resolve this problem but without success.
“Over time, the singularity concept has become an established dogma. People just let it be.
“But a Man of Dartmouth would not let it be. He worked on this mystery for 50 years and the answer emerged eventually from his senior fellow thesis. Here is the secret.
“Black holes are rotating bodies. A rotating body has a rotational inertia which keeps it rotating at a steady rate. If one tries to speed up or slow down its rotation, one must apply a tangential force in order to do so. A singularity does not have a rotational inertia because it is a point.
“The rotational inertia also determines the structure of a body. Take an ordinary example. Two eggs have the same size, shape, and weight. They are indistinguishable. However, one egg is a raw egg and the other one hard-boiled. Now rotation will tell them apart. The hard-boiled egg rotates easily while the raw egg rotates sluggishly. They have different rotational inertia and internal structure. For black holes, Man of Dartmouth found that every black hole has a rotational inertia showing it has a structure. There is an effective radius which is the radius of gyration known in mechanics.
“So what is the significance if black holes have a structure? Is it that important for astrophysics? The significance is scientific because the theorem that proclaims the singularity was recognized for the Nobel Prize in 2020. However, the black hole structure contradicts the singularity. We notice that major progress and paradigm shift in a given field occurs once every 50 years and this has been the case in science for several hundred years. A paradigm shift for black holes is inevitable. A notable example of a paradigm shift is the continental drift theory which contradicts the previous immovable continent dogma. The dogma was vigorously defended by the then leading authorities in geophysics for decades until it finally faded away.”
An exuberant Yuan may be contacted at yha@ccp.edu.
—Val Armento, 227 Sylvan Ave., San Mateo, CA 94403; valerie.j.armento.73@dartmouth.edu