The most robust quantum theory can’t explain dark matter. Courtesy | Twitter
Physicists cannot explain why we are not black holes, according to Assistant Professor of Physics Nathan Herring.
Physicists are developing theories of the universe which combine all the fundamental principles of physics, according to Herring in a Nov. 2 speech called “Physics at the Frontier: Where are We Going in Fundamental Physics?”
Herring said these theories fail to explain many things, like why particles do not collapse into black holes.
“We are living in possibly one of the most exciting centuries for physics, because the questions we’re asking now are just so deep and structural and surprising,” Herring said. “It’s amazing that we can even start to address them in the language of physics.”
The Core Theory is the closest physicists have come to a universal equation that combines all the fundamental principles of physics, according to Herring. He said it forms the foundation of physicists’ most robust quantum theory, the Standard Model, which categorizes fundamental particles and makes predictions about their properties.
“You can use this theory to explain what’s happening in the early universe and it works quite well,” Herring said. “It is very cool.”
There are major observations, however, that the Standard Model cannot explain.
“We are victims of our success and curiosity, because the theory works so well,” Herring said. “There are things we don’t understand about it. And there are paradoxes in the theory, and we would like to resolve those.”
One paradox is that the universe needs more matter than what physicists can see with a telescope, according to Herring.
Compared to pictures of the early universe, Herring said some matter has “disappeared” from our view, converting into a new form of matter that does not interact with light. The Standard Model cannot explain this mysterious matter, which physicists have called “dark matter.”
“Astronomical observations agree that about 32% of the universe’s energy density is some cold, slow-moving matter,” Herring said. “Only 5% is stuff that interacts with light, namely stuff made of atoms.”
The Standard Model also creates another problem. Herring said it predicts that particles should have more mass than experiments show — so much that they collapse into black holes.
Herring said this is because the Higgs Boson, a particle that affects the mass of other particles, is less massive than it should be according to the Standard Model.
“This is actually good,” Herring said. “If the Higgs boson mass was too heavy, it could be so heavy that it would make everything else heavier. Hence, everything could be a black hole.”
Herring said possible solutions to these problems include either sacrificing one of the principles of physics or combining them in a new way.
“Before we start just throwing things out on the board like crazy, we should do our best to make sure we really understand what the theory needs,” Herring said, “and that’s what a lot of my work has been on as a researcher is to try to understand what really happens when you combine these principles in certain situations.”
Students walked away from the talk with a new appreciation for physics.
“It is interesting to kind of make things fit with each other on the scale of dark energy,” freshman Ben Bassett said.
Other students were intrigued by the limits of established theories.
“We have something that works in certain scenarios and in this scenario completely falls apart, which is just really interesting,” freshman Alex Heredia said.
Herring said he hoped his talk inspired students to accept the challenge of solving these physics problems.
“If you’re a student, as you can see, there’s a lot of cool stuff to work on,” Herring said. “Physics is not dead.”
