In the 20th century, scientists sought out the building blocks of reality: the molecules, atoms and elementary particles out of which all matter is made the cells, proteins and genes that make life possible the bits, algorithms and networks that form the foundation of information and intelligence, both human and artificial. Many potential “exotic” phases, made possible by the bizarre consequences of quantum mechanics, have been cataloged in theoretical explorations, and we can now start realizing these possibilities in the lab with specially designed materials.Īll of this is part of a much larger shift in the very scope of science, from studying what is to what could be. For example, physics has moved far beyond the simple phases of matter of high school courses - solid, liquid, gas. Instead of studying a natural phenomenon, and subsequently discovering a law of nature, one could first design a new law and then reverse engineer a system that actually displays the phenomena described by the law. So, like the fictional Baron Munchausen who lifted himself out of a swamp by pulling on his own hair, physics is self-sustaining - it can use itself to produce new fundamental insights, which can then be captured in rigorous mathematics.Ĭonfronted with the endless number of physical systems we could fabricate out of the currently known fundamental pieces of the universe, I begin to imagine an upside-down view of physics. These “phonons” are elementary packets, or “quanta,” of sound, and their behavior is similar to that of photons, the quanta of light. By using the rules of quantum theory, these waves themselves can be described in terms of particles. A simple example is sound waves, the synchronized oscillations of molecules of matter. They can also “emerge” out of the collective behavior of many constituents. The truth is, the realm of the smallest particles is not the only place you can find the fundamental laws of physics. Learning the rules of chess doesn’t make you a grandmaster. Claiming that physics is finished is akin to arguing that mathematics ended after the introduction of natural numbers and basic arithmetic, or that chemistry was over with the advent of the periodic table. The aim of physics is to understand in a precise, mathematical way all manifestation of matter and energy in the universe - and we have barely started to explore this infinitude of possibilities. In fact, I believe that what we currently know is an absolutely negligible fraction of the physics that’s out there, waiting to be investigated. It ignores a large part of the discipline, and vastly underestimates what we can still achieve. The third reason the reports of the death of physics are greatly exaggerated comes from a more fundamental and categorical mistake: Defining progress in terms of discovering new particles or forces is a myopic view of physics. (I might also add that understanding 5 percent of a subject is in itself a wonderful achievement.) As long as such mysteries remain - and there are others - the work of physics will not be complete. These missing parts consist of dark matter and dark energy, both equally mysterious forms of new physics. Recent advances in cosmology allow us to state, with a fair amount of certainty, that 95 percent of the universe is missing.

Maybe physics has run out of original ideas? Black holes and gravitational waves are direct consequences of the equations Albert Einstein discovered in 1915. All three were rare instances of scientific mega-events that landed on the front pages of newspapers and captured the imagination of the world.īut, one could argue, the seeds that led to these discoveries were all planted in the good old days.

We saw the discovery of the Higgs particle in 2012, the detection of gravitational waves in 2015 (announced in 2016) and the first image of a black hole’s event horizon in 2019. First of all, for a subject supposedly past its prime, the first two decades of this century have been pretty successful for physics. I believe this point of view is wrong, in at least three distinct ways. Nowadays, people worry about a “desert scenario,” where no new particles will be found for many decades to come, if ever. This relegates physics to the previous century - the golden days when the revolutions of relativity and quantum mechanics shook the world, and the discoveries of elementary particles led to a string of Nobel Prizes. Is physics finished? The 21st century is often called the age of biology.

Simple physics phenomena