We mentioned last time, as the theory proposed by Maxwell got proved by Hertz’s experiment, the wave theory of light finally became an unshakable fact.
The wave was so mighty that it beat the particle to the ground and established its own unprecedented empire. Not long after that its realm would spread across the whole frequency band of electromagnetic waves, from microwave to X-ray, from ultraviolet to infra-red, from r(garma)-ray to radio wave ... The common light is only a small country under its reign.
Hertz’s experiment also marked the peak of classical physics. The mansion of physics was never this spectacular before. Newton’s mechanics was impressive enough, and now Maxwell built another infrastructure upon it. Electromagnetic theory was incredibly perfect in maths. After the rearrangement by Hertz and others, the theory firstly proposed by Maxwell gave out an elegant core, which was the famous Maxwell equation group. As soon as it got published, people were amazed by its simplicity, profoundness and symmetry. Later, Ludwig Boltzmann cited the poem from Goethe, “Were they written by God?” Until today, Maxwell equation group is still acknowledged to be a model for the beauty of science. Many great scientists bowed down before its charm. They asserted that: as for a scientific theory, the simplicity and elegance are more important than the accuracy of its data. It’s a great theory from any aspect. Roger Penrose in his The Emperor’s New Mind put it along as Newton’s mechanics, the relativity theory and the quantum theory and called it a “Superb” theory.
Physics conquered the world. In the late 19th century, its power ruled over every phenomenon people knew. From the planet in the universe to a stone on the ground, everything operated according to its rules. The discovery of Neptune was one of its greatest victories. In optics, wave had already unified the world. The new electromagnetic theory expanded its glory to the whole world of electromagnitics. In thermal physics, the three laws of thermodynamics had almost built up (the third law had got its prototype already). And with the efforts of Van der Waals, Maxwell, Boltzmann, and Josiah Willard Gibbs, the kinetic theory of molecules and statistical thermodynamics had been established. More amazingly, these all conformed with each other, forming a great union of classic physics. Classic mechanics, classic electrodynamics, and classic thermodynamics (plus statistical dynamics) formed the 3 fundamental columns of the physical world.
Those were the days of great glory, the golden age of classic physics. People might final believe that the secret of God’s creation had been mastered completely. It made much sense: almost every phenomenon in the physical world could find one explanation. People thought they had discovered all the basic principles in the world. Physics was perfect and flawless. There would never be a breakthrough anymore. And what people could do now is to amend some details and to measure some constant to a more accurate digit. Planck’s adviser even suggest him he should stop wasting time researching this highly mature system.
If we look retrospectively, Hertz’s electromagnetic wave experiment in 1887, on the one hand laid the last cornerstone of the electromagnetic theory, but on the other hand, it also buried a self-destruction weapon for classic physics.
Let’s go back to the first section of our story: in that lab in Karlsruhe, in the opening of Hertz’s copper ring acceptor, a spark sparkled continuously revealing the existence of electromagnetic wave. But this spark was weak and hard to observe, then Hertz isolated it out in a dark environment. In order to make a perfect effect, he even isolated out the lights from the sparkles of the generator, not to let them interfere the acceptor.
At that moment, something strange happened: when there was no light upon the acceptor, the distance that the spark could travel was greatly shortened. In other words, if there was no light, the spark could only be generated when the two balls were very close to each other. And if we let the acceptor be exposed to light again, it would become easier again to get the spark.
Hertz had no idea about this strange phenomenon, but he kept the record of it, and wrote it into an essay with the title On The Effect Of Ultraviolet Light In The Discharge Of Electricity. Although this essay got published, it didn’t arose much attention from the public. At that time, the “Malconi”s were thrilled because of a giant business opportunity. Even Hertz himself didn’t realize that he touched the sleeping soul of quantum. Though it had not been evoked, it left a terrible curse to the newly arrived electromagnetic theory.
It’s a pity that Hertz passed away so early that he didn’t witness the change that quantum has brought to the world.
A string of unexpected discoveries were made during the last few years in the 19th century, and they seemed to foretell something:
In 1895, Wilhelm Konrad Rontgen discovered X-ray.
In 1896, Antoine Herni Becquerel discovered the radioactivity of uranium.
In 1897, Marie Curie and her husband Pierre Curie discovered more radioactive elements: polonium and radium.
In 1897, Joseph John Thomson regarded the cathode ray as a string of negatively charged particles. Electrons were discovered.
In 1899, Ernest Rutherford discovered the transmutation of elements.
So many new discoveries dazzled people’s eyes. Everybody felt a sense of uneasiness. Something significant seemed to be around the corner. People raised their eyes, finding two dark clouds hanging over the corner of the sky. The clouds were small and almost unnoticeable.
But before the coming of the storm, let’s look at the sky of the golden age again. The golden light shines upon our faces, dyeing our faces with the color of holiness. The grand mansion of classic physics under its glory looks so magnificent. It reminds us of the eternal palace for Zeus and other gods on Mount Olympus.
Nobody could know this stunning magnificence would be the last brilliance of the sinking twilight sun.
