Tuesday August 16, 2016
The Ultimate Simplicity of Everything
Some physicists now claim that we may have reached the end of what physics can discover about the origins and structure of the universe. Neil Turok is definitely not one of them. Director of the Perimeter Institute for Theoretical Physics and former Massey Lecturer, Neil believes that the universe "invites" us to figure it out, by giving us clues about its composition. And when we follow its clues, we discover that it's ultimately quite simple. This episode is based on a public lecture and subsequent conversation with host, Paul Kennedy. **This episode originally aired March 14, 2016.
What's behind the end of physics?
Neil Turok: We live in very pessimistic times in spite of the massive discoveries that are being made. It's one of the great ironies that at the moment where at the time the Large Hadron Collider discovered the Higgs Boson fifty years after it was predicted. When LIGO discovered the gravitational waves from black holes a hundred years after they were predicted. When we have mapped the entire visible universe using the Planck satellite, everybody -- well, not everybody -- some people are wringing their hands and saying this is the end of science. It couldn't be more absurd. What underlies it, I think, is the fact that to a large extent over the last nearly hundred years, the great revolutionary ideas of the early 20th century have been playing out. To a very large extent, the entire history of physics since the 1900s, the 1910s, the 1920s, it's been more or less working out the consequences of the great ideas of that time which were relativity -- meaning what is space and what is time -- and quantum mechanics -- the laws of physics, how things work within spacetime. And so I think, to some extent, what these people are expressing is that there haven't been radically new revolutionary ideas. Physics is a pretty conservative field. You know, it's about absolutely secure knowledge -- that is physics. It's our most secure knowledge. Maybe behind logic, closely behind logic. Logic can be very secure, I mean mathematical logic, but it can be irrelevant to the world. Physics is all about the world. Our most secure knowledge about the world, about the natural world, is physics.
And I think what people are sort of expressing is that we haven't had a big revolution in physics. String theory was hoped for to be that revolution in the 1980s but it hasn't really panned out in the sense that it hasn't given a single prediction. Instead it's given us a huge collection of theories where, if you like, there's no overarching theory to tell which particular version of string theory is the one that describes the world. It's almost self-destructed, I would say because it turned out to be not just one theory but this vast collection of theories which could all give different descriptions of the world.
So I think that sort of theoretical catastrophe, as I view it -- meaning the logical pursuit of quantum mechanics and relativity over a hundred years was tremendously successful at some level but finding its own successor theory, it hasn't been successful. I think that is also laying the ground for some sort of revolutionary change in the sense that we basically will have to go back to the founding principles. It looks like the founding principles of modern physics -- quantum theory and relativity -- have played out and they have not given us the answers we need. And so we have to go back and question those founding principles and find whatever it is, whatever new principle will replace them. So matching these great puzzles posed by the observations are equally great puzzles in our fundamental theories. And so that is just a wonderful thing to contemplate in itself. I mean, partly people become very pessimistic and say, oh my god, I've devoted 50 years of my life to studying this incredibly technical and difficult theory and now I find it's blown up in my face, it's not giving any predictions at all...and so some people talk about the multiverse where the universe would be wild and chaotic on large scales and almost anything you could imagine would actually exist somewhere in the universe. I mean, this is literally a scenario which became very popular among a category of physicists, that there is a multiverse out there. Yet the evidence is exactly the opposite. That, as we look around us, things could not be simpler. There's no evidence for chaos on large scales in the universe. It's totally the opposite. It's pristine, elegance, minimalism is all we see. So, I think this is a very, very exciting time to be doing theory. The challenge is enormous. The clues are enormous. We're waiting and we're preparing and we're encouraging people to take radical leaps.
Some visuals from Neil Turok's lecture:
The map of the universe shows amazing symmetry and uniformity across all scales.
The universe is shaped like a giant bell lying on its side. The bell was struck nearly 14 billion years and emerged in oscillating waves from the singularity.
A view of the universe as we are able to see it. The red ring is the earliest known part beyond which we can't see.
Watch Neil Turok's Public Lecture: The Astonishing Simplicity of Everything