7 minute read
Ulf Danielsson – professor of physics and popular educator
His calm and methodical way of explaining the most advanced cosmological concepts has made him much in demand for everything from lectures and debates to radio and TV programmes. After five books, many awards and academic roles, the question is what new goals lie ahead for the professor. “I am very glad just to be where I am,” says Ulf Danielsson, Professor of Theoretical Physics.
text ANNELI BJÖRKMAN photo MIKAEL WALLERSTEDT
PROFESSOR PHYSICS AND POPULAR EDUCATOR AND
PROFESSOR OF PHYSICS AND POPULAR EDUCATOR
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ON THE SAME DAY as the interview, the news arrived that an international team of scientists had succeeded in taking the first picture of a super-massive black hole in the centre of the Milky Way. The media were quick to contact Ulf Danielsson for his comments – a well-established practice. Few researchers have the same ability to make concepts such as black holes and string theory seem comprehensible. Fortunately, the professor from Uppsala never seems to tire of trying to explain the state of things, or at least of the universe.
“Basically, it comes down to my own curiosity. It’s my desire to understand these issues that drives me, that’s the objective. Then of course it’s fun to be able to contribute a bit to the whole business,” says Danielsson.
IT IS JUST OVER THIRTY YEARS since he began to research how string theory in particular could offer answers to how the universe was created. One of the really great mysteries in modern physics concerns cosmology and especially the fact that the universe is expanding more and more quickly. The reason is believed to be what is known as dark energy.
“Basically, dark energy is a constant energy density that exists in the universe. Since it has been demonstrated to be able to cause accelerating expansion, it could be behind the fact that the galaxies are moving apart more and more quickly. We are now in the process of measuring this very precisely with large telescopes.”
According to string theory, the smallest constituent parts of matter, such as protons and electrons, take the form of vibrating ‘strings’. Ulf Danielsson designs mathematical models so as to be able to develop this theory.
“In practice it isn’t all that grand. You find some little corner, some little mathematical problem or something you’re trying to solve, so what you’re doing is building on what other people have done where you feel you have something to add. Then someone else can use it to build up a realistic model. And some other person looks at how this model can be adapted to observations, while yet another makes the observations.”
HE EMPHASISES THAT the mathematics
Few theoretical physicists have had as much public impact as Ulf Danielsson. is merely a tool, not a goal in itself: it is all about solving real problems and understanding how the universe is organised. The path to such an overall understanding is via the concept of curved space-time, part of Einstein’s gravitation theory of how every gravitating mass changes the geometry of space and curves time. The thing that puts a spanner in the works for the scientists is the existence of black holes, whose gravitation is so strong that not even light can escape them.
“Black holes are mysterious. Partly because we still have not fully succeeded in fusing together Einstein’s general theory of relativity and quantum mechanics into one general theory,” explains Danielsson.
Some progress has been made, however. When black holes collide, gravitational radiation is emitted that we can now capture in the powerful radio telescopes of the Event
"Knowledge of the universe is important to me, it has to do with a picture of the world where I’m trying to make everything fit together," says Ulf Danielsson, Professor of Theoretical Physics.
Horizon Telescope network. Danielsson believes that such observations can give us new ideas about the structure of black holes. But he also points out that it is not generally possible to plan for new discoveries.
“With large and expensive facilities, we must prioritise and attempt to make efforts as best we can. But in general, when it comes to processing all this data that comes in, as well as other types of research, I think that we need to be more permissive about thinking more freely. We must encourage it in a different way than now.”
HE HAS FOUND AN OUTLET for his own creativity and curiosity in many different areas and contexts. As well as being a regular contributor to Radio P1, contributing to TV programmes and being heard in pods, Danielsson has also performed at the Royal Dramatic Theatre in Stockholm. In 2018 he took part in Performance Lecture: About the Universe, in which he gave a cosmic overview of the history of the universe.
“What made that so enjoyable was to be able to live the dramaturgical aspects and convey a narrative, and weave it together with a greater story.”
His popular science books on physics and
natural science can also be seen as part of a larger narrative. They fit questions that have been important to him at various times in his life into a broader discussion of modern physics and the mathematical-scientific world view. He has given points of view on everything from climate and natural history, philosophy and world views to technology and artificial intelligence.
But in the autumn a different kind of book will be published: Handbook for Citizens of the Universe, of which Danielsson calls himself the editor.
“THOSE WHO ARE BEHIND THE BOOK are a collection of extraterrestrial civilisations that have written to mankind to try to explain where we stand. The extraterrestrials are very secretive and do not reveal anything we don’t already know about basic physics. Because it would be dangerous for us to acquire knowledge that we are not mature enough to handle. On the other hand, they are extremely generous about revealing some things about how other civilisations have got on in other parts of the universe,” he smiles.
He thinks that writing books is just getting more and more fun. As he puts it, in his books he can give himself a free rein and try to explain and describe the world in a new way for anyone who cares to listen. But when asked about his teaching, he gets an extra glint in the eye.
“If I am teaching a course on electromagnetism, it’s just so much fun to get the students to try to understand the physics, the experiments, the equations, everything! When you look at these mathematical equations and how you can lead from one to another and how you can explain experiments that they have actually been able to do themselves – that’s quite fantastic! That’s when it can become a really emotional experience, when things suddenly start to mean something and to move you. Then you simply can’t resist it. You simply have to find out more.” ●
Ulf Danielsson
Title:
Professor of Theoretical Physics at Uppsala University.
Selected positions:
ViceRector of the Disciplinary Domain of Science and Technology, Uppsala University, 2011–2014; member of the Royal Swedish Academy of Sciences, the Royal Society of Arts and Sciences of Uppsala and the Royal Society of Sciences at Uppsala
Selected prizes and distinctions:
Disa Prize 2005, Göran Gustafsson Prize for physics 2008, Thuréus Prize 2009, H.M. The King’s Medal, 8th size, with the ribbon of the Order of the Seraphim 2022 “for outstanding contributions to popular education as a theoretical physicist”.
Hidden talent:
“My partner says that I am very good at deciding whether an avocado is ripe or not, which is a mystery to both her and me since I have poor colour vision. On the other hand, I am very bad at identifying the ripeness of bananas.”
If I had not become a scientist:
“Then I would probably have been a forest warden like my father. Being out in nature like that and still having the quite intellectual job of planning the forest management to get everything to work out, that combines reflection with experience of nature. In that way, the similarity with theoretical physics is quite striking.”
