A ciascuno il suo
At the turn of the 20th century, finding a new form of radiation could put a physicist’s career on the fast track. Wilhelm Röntgen changed the world by discovering X-rays in 1895. Soon thereafter, Ernest Rutherford and Paul Villard identified three different kinds of radiation, dubbed alpha, beta, and gamma rays, emitted by radioactive compounds. In 1903 French scientist René Blondlot added to the frenzy with his announcement of N-rays, a strangely democratic form of radiation emitted by wood, iron, living organisms—just about anything at all.
Some 300 scientific papers were written about N-rays. There was just one problem: They weren’t real. A skeptical physicist named Robert Wood visited Blondlot’s lab and secretly removed a key part of his apparatus; this had no effect on Blondlot’s perception of N-rays, showing that they were purely a product of the imagination. (…)
The modern version of the search for new kinds of radiation is the search for new forces of nature. And while there may be unknown forces waiting to be discovered, we can say with great confidence that such forces must be so feeble that only a professional physicist like me would really care. (…)
According to modern physics, the world is fundamentally composed of particles interacting via forces. Over the course of the 20th century, researchers discovered many new particles interacting in many different ways. But it gradually became clear that the vast majority of such particles are merely different combinations of smaller ones, and the great variety of interactions boils down to just a few forces. When the dust settled in the 1970s, we were left with two kinds of elementary particles: quarks, which group into heavier composites like protons and neutrons; and lighter particles called leptons, like the electron and the neutrino, which can move freely without bunching into heavier combinations.
Amazingly, these particles interact through just four different forces. Two are familiar—gravity and electromagnetism. (…) The other two forces are the strong nuclear force and the weak nuclear force. (…)
How can we be so sure there aren’t other forces that we just haven’t yet been clever enough to find? The answer is, we can look for them. We know where to look, and indeed we have looked. Other forces are not out there, at least not to any significant extent. Any new force we might someday discover must be so impotent over everyday distances that there’s no way it can affect the macroscopic world. If it could, we would already have found it.
painting { Linnea Strid }
