The theory of quantum energy was born on December 14, 1900, when the german Max Planck presented the result of an investigation into an obscure phenomenon, both in what it meant for the physics of the time and in the name: it was the problem of blackbody radiation. In physics, a black body is an excellent radiator: it absorbs all the energy that reaches it and, therefore, its appearance is black (of a body, we see the color that it reflects and does not absorb). Later, that absorbed energy is emitted in a very particular way. The problem was that since 1859 no one had found a formula to explain it. Like Wilhelm Wien in 1896, some physicists had found approximate formulas, but no one had given the exact solution. One afternoon in October 1900, he was visited by a colleague named Rubens, who had worked on the problem. After Rubens left, Planck sat down and a few hours later had obtained a formula that faithfully reproduced the experimental results for observing quantum energy.
The End of Classical Physics
It is one thing to find a formula simply by fitting the data to a theoretical curve and quite another to deduce it from first principles. Planck was obsessed with deriving the formula from current physical theories. Planck worked hard, and in the end, he realized that he could only deduce it if he assumed something previously unthinkable: he had to renounce classical physics and admit that matter does not continuously absorb or emit energy.
Exploring Quantum Energy
A living being is made up of cells that in turn are made up of atoms. For centuries these were thought to be indivisible and elemental. However, today we know that they have electrons that circle a nucleus of protons and neutrons. In turn, these are made up of particles called QUARKS. We still do not know what is behind them, if there is anything. However, science is already looking for a last and perfect superparticle that encompasses the four forces of nature and the constituents of matter. It was an act of desperation because a theoretical interpretation had to be found at all costs. Planck’s idea was that matter could neither absorb nor emit radiation in smaller and smaller amounts, without limit. There is a minimum amount of energy below which it cannot be lowered. In addition to the black body, another inexplicable phenomenon was the photoelectric effect. We’ve all seen it work on elevator doors and escalators. Its operation is straightforward. When light with specific energy falls on a certain type of metal, it emits an electron. This phenomenon could not be explained correctly by classical physics, but in 1906 a young physicist named Albert Einstein published an article that would earn him the Nobel Prize. His proposal was even bolder than Planck’s: not only does matter emit and absorb quantum energy, but energy itself is quantized. The photoelectric effect is fully explained if it is assumed that light is composed of tiny particles, which he named photons.
Rutherford and Bohr
On one side were the atomic spectra, the fingerprints of the different chemical elements, which there was no way to explain their origin. On the other hand, in 1909, the New Zealander Ernest Rutherford showed that the atom was composed of a tiny nucleus, which contained practically the atom’s entire mass, with electrons circling it. Now, according to the physics of the moment, the electrons had to lose quantum energy and end up falling on the nucleus. The matter could not exist, but it was there. This unfortunate state of affairs was partially resolved by a brilliant Dane named Níels Bohr. In 1913 he proposed that electrons cannot go around the nucleus in whatever orbit they want, but rather in pre-set ones. Moreover, to pass from one orbit to another, the electron must absorb or emit (that depends on whether it is moving away from or towards the nucleus) a photon of light with the same quantum energy that the change of orbit requires. In this way, the spectrum of the simplest atom, hydrogen, could be explained. The publication of Bohr’s article marked the beginning of the end for the classical worldview. But the worst was yet to come. Einstein had shown that light had two natures: corpuscular, with the pellets fired at a fair, and undulating, like the waves in a pond. In 1924 the Frenchman Louis de Broglie stated that the Balinese did not always have to behave like Balinese; they could also behave like the waves in the pond.
Formulating the New Theory
In the early 1920s, Clinton Joseph Davisson, a physicist at Bell Telephone, was bombarding nickel crystals with electrons. He observed some regularities in how electrons were scattered across the crystal’s surface but could not understand the importance of what he observed.
Nobel laureate in chemistry Ernest Rutherford presented a model of an atom similar to the Solar System, it was made up of a central nucleus and satellite electrons orbiting around it. It was a doctoral thesis that shed light on the matter. De Broglie, the connoisseur of the work of Einstein and Bohr, proposed electrons should be given a wave nature. With this revolutionary idea in hand, de Broglie was able to explain, in terms of strictly wave phenomena, Bohr’s permitted orbits for the atom. Three years later, Davidson was repeating his experiments together with a younger colleague, Lester Halbert Germer. They observed that the curious distribution of the electrons was only explicable if they behaved like waves. Another young physicist took the next step in 1925: Werner Heisenberg. He believed that the idea of electrons orbiting around the nucleus was misplaced; no one had seen them. The only thing that could be seen were the photons emitted by the electrons as they changed “orbit.” Then this was the only thing that had to be taken into account. In this way, Heisenberg created a mathematical scheme known as matrix mechanics, with which he was capable of reproducing the results of the old theory of quantum energy.
Everything is Possible
Around the same time, another German, Erwin Schrodinger, offered a mathematical formulation of de Broglie waves: thus, wave mechanics, the basic tool of theoretical physicists, was born. Heisenberg did not like it at all since it made us suppose that these “waves” really existed. It would be Max Bom who showed that they were nothing more than mathematical devices used to calculate the probability of finding an electron in a region of space. Furthermore, Paul A. M. Dirac pointed out that both Heisenberg and Schrodinger were right: their two formulations were equivalent ways of representing what has since become known as quantum mechanics.
The break with the classical world, the world that our eyes see, has now become definitive. Quantum energy mechanics proposed a probabilistic view of the world: the pellet is not in a certain place, but there is a certain probability that it is there. It is possible to find him anywhere in the universe—a high price for wanting to understand the secrets of the matter.