Why can’t quantum theory and relativity get along? – Brantford Expositor

There are many popular memes on the Internet that have to do with differing perceptions.

They have multiple photos captioned: What I think I do; What my friends think I do; What my mother thinks I do; and, finally, What I really do.

The pictures usually show wildly differing perceptions of the same job. This also appears to be the case with science. There is often a vast gulf between what people think about science and what it truly is.

Most people tend to think of science as the queen of the intellectual disciplines - always sure and precise, having all the answers to any conceivable question. Sadly, nothing could be further from the truth. Even science itself recognized this as truth with the division between theoretical and practical sciences.

If science is the queen of intellectual disciplines, Physics is the king of science. It is the fundamental investigation into how the world around us works. It includes chemistry, biology, mechanics and just about anything else you can think of. Physics stands astride of science like a Colossus, proud, sure and confident. But this is only a faade. There is a fundamental contradiction inside physics that has defied explanation for the past 100 years. And we are, even now, only beginning to glimpse some faint ideas about how this contradiction can be resolved.

In physics, there are two theories that form the basis for our understanding of the universe. Quantum physics that has explained how matter is constructed and why it behaves the way that it does. Most nuclear physics deals almost exclusively with quantum physics.

On the other end of the spectrum of physics knowledge is relativity. One man, Albert Einstein, whose very name has become another way of saying genius, was responsible for this wonderful theory that is master of everything large. It deals with the structure of the universe, the nature of gravity and explains space and time. It is a theory that has stood every test that has been put to it and it has never failed to produce the expected results or even a slight deviation from the expected results.

Both quantum theory and relativity are two of the most successful theories that we have ever had. The problem is that they don't play well together. That's right, two theories that are as close to reality as we have ever come are not compatible with each other. Doesn't make sense, does it? When you try to apply relativity to the very small scales of the atomic realm, suddenly the mathematics does not make sense any more. Quantities become infinite and predictions go wildly astray.

How is this possible?

If I could answer that question, I would be preparing my speech for my Nobel Prize ceremony. The thing that makes this amazing is that each theory is so close to describing reality that it is almost inconceivable that it could be incorrect. If either or, indeed, both theories are wrong, it will bring about a complete revolution in our understanding of reality.

Some years ago, I visited CERN in Geneva just a couple of months before its discovery of the Higgs particle that controls the mass of matter. CERN is the world's largest scientific apparatus and is designed to smash atoms together at almost the speed of light and then analyze the pieces to understand how matter works. I managed to have lunch in the cafeteria there with some of the scientists working on this marvellous machine. Sitting not too far away were at least two Nobel Prize winners who were doing work at CERN.

The conversation took an interesting turn when I asked them what would happen if the machine did not find evidence of the Higgs particle. The fellow I was talking to got a faraway look in his eyes and said; "Then physics would become very interesting. Something unexpected means that we don't understand it all and we would have to become very creative to figure out what is going on because everything else fits our current theories."

Nobel laureate Richard Feynman agreed with this assessment when he said that physics required a great deal of imagination, but imagination in a straitjacket. This means that you cannot imagine anything you like. What you theorize must also conform to everything we already know. In other words, any new theory must not only explain the new phenomena, but must still provide an explanation for all the old phenomena as well, or, at the very least, not be incompatible with what we observe.

This is the situation for modern physics. We have two incredibly detailed and effective theories of how various parts of nature work, and they are not compatible.

It would seem that physics is indeed "interesting again."

Tim Philp has enjoyed science since he was old enough to read. Having worked in technical fields all his life, he shares his love of science with readers weekly. He can be reached by e-mail at: tphilp@bfree.on.ca or via snail mail c/o The Expositor.

Brantford Expositor 2017

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Why can't quantum theory and relativity get along? - Brantford Expositor