Part One

The Future,

In Theory

Lee Smolin

The Future of the Nature

of the Universe

We are asked to predict the state of our science fifty years from today. Fifty years is a long time, given the pace at which physics and cosmology have progressed over the last several hundred years. But perhaps it is not too long a time to make predictions that will not seem entirely stupid by then. If you look back over the history of science, you will see that often the important questions people were asking had been answered fifty years later. And yet the progress of science has usually been slow enough that people speak roughly the same language as their colleagues working in the same field fifty years earlier.

Let's look back fifty years, then, and note what the big questions were. My own list would include:

1)What is the nature of the strong force that holds atomic nuclei together?

2)What is the nature of the weak force responsible for radioactive decay?

3)Is the Steady State model of the universe right, or might there have been a Big Bang, as speculated by Gamow and other fringe figures?

4)Do protons and neutrons have any internal structure?

5)Why do the proton and neutron have slightly different masses, while the electron is much lighter than either? Why is the neutrino massless? What is the muon and who ordered it?

6)What is the relationship between general relativity and quantum theory?

7)What is the right way to understand the quantum theory?

I think we can confidently assert that now we know the answers to the first four questions. We are still working on the last three. But the first have not been forgotten; indeed, the ...