Revolutionary Rumblings

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Surprising though it might seem, most physicists have strong revolutionary sympathies. From Galileo to Kepler, Newton to Einstein, the most successful natural scientists in history have all tended to buck the established wisdom of their day as they boldly led us towards profoundly deeper levels of understanding about the world around us. The most recent revolutionary period occurred a little more than a century ago and was perhaps the most profound of all, consisting of two near-simultaneous overthrows of conventional wisdom that eventually resulted in today’s twin pillars of relativity theory and quantum mechanics, completely overhauling how we look at space, time, matter and energy.

A characteristic feature of revolutions, however, is that, most of the time, you don’t see them coming. Lord Kelvin, an impressively accomplished scientist who did fundamental work in both electricity and thermodynamics (for whom the Kelvin temperature scale is named), is now perhaps best remembered for one of the most ill-timed prognostications in scientific history.

There is nothing new to be discovered in physics now,” he summarily declared to a group of physicists at the British Association for the Advancement of Science, “all that remains is more precise measurements.

That’s a dangerous sentiment to voice at any moment, but Kelvin’s timing turned out to be particularly disastrous, given that he gave this speech in early 1900, only 5 years before Einstein’s first paper on special relativity (among other things), and mere months before Planck’s blackbody radiation postulate that led inexorably to quantum theory. Such lessons from history are foremost in the mind of University of Pennsylvania physicist Justin Khoury these days. Justin works at the interface of particle physics and cosmology, and, as such, happily finds himself enmeshed in two of the greatest scientific mysteries of our, or any, age: dark matter and dark energy.

“We don’t know what these entities are, but there’s a proposal out there that dark matter consists of weakly interacting particles and dark energy is a form of vacuum energy; and those ideas, by-and-large, work well against the data.

“Now there’s a sense – a fairly widespread sense – that the field is in this butterfly-collecting mode: that we just need to cross the t’s and dot the i’s and we’re reaching the end. But, of course, that’s a pitfall, as we know from history; one has to be careful.

“It may be that this is what dark matter and dark energy is, but it could also be that we’re in for some surprises.”

But often, in order to become confronted with the unexpected, one has to at least be prepared to look for it in the first place. And one thing that particularly concerns Khoury is that, as cosmology has transformed itself from an arena of hand-waving speculation into a rigorous data-driven domain on the back of decades of increasingly precise observations of the cosmic microwave background, it has fallen prey to an increased unwillingness to countenance views outside of its established mainstream.

“One of the downsides to having all of this data and the science maturing, if you will, is that the field has also become more conservative. Maybe that’s a good thing, because we want to converge at some level, but there is a definite worry now that it’s become less accepting of new ideas. New ideas are never nicely packaged: when they come out, they’re typically ill-formed. And if they’re constantly being shut down, then we may be missing out on something.

That’s one thing that I’ve definitely observed from the time I was a graduate student. Back then, we came up with this crazy idea about the early universe; and, at the time this was more or less – not accepted – but there was a certain open-mindedness about it. Whereas I think that nowadays, 15 years later, such an idea would be much harder to propose.

pendulum“Maybe it’s a natural pendulum swing: before it was the Wild West and now we’re in the conservative part of the swing, but I hope there will be a ‘market correction’, where we go back to a more open-minded attitude. It’s important, because the new ideas will come from young people. That’s usually the case, that young people will transform the field. I don’t want to be in a situation where, a hundred years from now, we discover what the correct theory was and we realize that we ignored this young person back in the early part of the 21st century who had that very idea – we shut her down. There are examples like that throughout history, and I just hope our field won’t be like that.”

Khoury’s concerns aren’t based simply on principles of fairness, or a well-honed historical awareness of the dangers of scientific hubris. He has a hunch that another profound scientific revolution is just around the corner, and all that is really needed to push things over the edge is a large infusion of young, dedicated, iconoclastic scientists.

“I think that we’re about to experience the same sort of revolution that happened at the beginning of the 20th century with the invention of relativity and quantum mechanics. If you’re a young person, I think it’s the perfect time to jump into this field and contribute something original. The problem with someone who’s been in the field for a long time like myself is that we get blasé – we think, ‘Oh no, this idea will go away’ and so forth, but young people don’t have that, and I think that’s really helpful and refreshing.

“So my message to young people out there is: Don’t be afraid to come in, propose new ideas, think outside the box and think about alternative systems that we’ve thought about in history that connect these different phenomena. 

“We need fresh blood.”

Howard Burton,

To best explore the topics raised in this post for teaching and learning, please see related video and print resources that are part of Ideas Roadshow’s IBDP Portal: Clips: Time to Dive In, Dark Matter, In Search of an Explanation; Compilations: Dark Matter, Cosmic Mysteries, Full-length video and eBook: Cosmological Conundrums, and more.

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