Quantum Physics is not Weird. On the Contrary.. Paul J. van Leeuwen

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      Figure 3.9: The movement of the earth in summer and winter with respect to the ether wind.

      If Michelson and Morley's interferometer was now to move through the stationary ether at 30 km/s, their calculations pointed out that the light perpendicular to the direction of movement would lag 10^-15 seconds behind the light traveling in the direction of movement of their set-up. The resulting path difference of about 300 nm (nanometer) should have been detected by their very accurate interferometer. This difference is of the same order as the wavelength of visible light, between 400 and 800 nm. A noticeable shift of the interference pattern should be observed.

      However, to their astonishment, no shift was detected. So, exit the ether. Or one would have to return to the geocentric universe of Ptolemy, the earth residing immovably at the centre of the universe. Which was of course not a viable option. Nonetheless, Edward Morley maintained his belief in the existence of the ether until his death. Their experiment, by the way, is still being repeated - every time with increased precision. So, in principle, the case is still undecided. But today's consensus is that the ether does not exist unless the opposite can be convincingly demonstrated.

      Albert Michelson received the Nobel Prize in physics in 1907 for his performance in optics and his contribution to physics. A considerable prize for a "failed" experiment.

      The classical view of the universe at the end of the 19th century

      The subject of the previous paragraphs was the rise and great success of classical physics. It has now hopefully become clear why, apart from a few imperfections, classical physics fits so seamlessly into our daily experience of material reality. We can summarize our own everyday experience of the world as follows:

       If I want to move something, I have to push it or pull it.

       What I perceive exists objectively and independently of me. The world seems to exist with or without me.

       Even when I am not looking at the moon, or when it has disappeared behind the horizon, I am sure that it is still 100% materially there.

       According to classical physics, my inner experience of reality is an image that coincides with the "real" world around me.

       Mathematics is the instrument to make a model of the world that explains exactly how it works.

       Causality, cause and effect, reigns absolute.

       The whole is just the sum of the parts. After analyzing the parts first, in principle the whole is known.

      In short, the world seems solid and permanent. According to most scientists, physics was considered to be almost complete in the second half of the 19th century, with the exception of a few problems. Smart young students like Max Planck were discouraged from pursuing a career in physics, because there would be no longer any honor to be gained in it. However, it would turn out differently.

      The electromagnetic spectrum

      In 1886, seven years after Maxwell's publication, Heinrich Hertz (1857-1894) confirmed the existence of standing electromagnetic (radio) waves with a wavelength of almost 61 meters (200 ft). It is probably not a coincidence that the depth of his laboratory was 30 meters, so that half that wavelength did fit precisely. Maxwell's theory was confirmed. Hertz saw no practical use for his discovery. Guglielmo Marconi (1874-1937) saw its application potential and realized the first radio communication in 1889. In 1896, shortly after that, the telegram service and the Morse code were invented. Nikola Tesla (1856-1943) forgot to patent his invention concerning sound communication using radio waves and the cunning Marconi received also the credits for that.

      In 1895, Wilhelm Röntgen (1845-1923) discovered highly energetic EM-waves he generated by applying a high voltage between the electrodes of a vacuum tube. Röntgen called his discovery X-rays.

      Figure 3.10: Albert von Kölliker's hand photographed by Röntgen.

      These X-rays have wavelengths between 0.01 and 10 nanometers. The first X-ray photos are those of Röntgen's acquaintances, see figure 3.10 for an X-ray of Albert von Kölliker's hand. Röntgen also took such an X-ray of his wife's hand. Upon seeing the result, she feared her end was near. It is incidentally remarkable that Röntgen made his discovery because he noticed that a screen covered with barium platinocyanide lit up in his darkened laboratory when he switched his vacuum device on. The fact that he had such a screen accidentally standing readily available in his laboratory, the fact that Röntgen noticed the effect of his device and the fact that he draw the right conclusion is an excellent example of serendipity, the accidental and unsolicited discovery ^[13]. Serendipitous discoveries abound in science.

      Physicists thus gradually discovered the entire spectrum of EM radiation, from radio waves with wavelengths of thousands of kilometers to gamma radiation with wavelengths of 10^-14 meters. Visible light is only a very small part of the full spectrum. The limits left and right of the spectrum in figure 3.11 are not the limits of EM radiation. There is no known absolute upper or lower limit of the EM spectrum.

      Figure 3.11: The EM-spectrum. Source: biology.stackexchange.com

      To the left of the gamma radiation and to the right of the radio waves the EM-spectrum continues infinitely. The limits in figure 3.11 are not fundamental, they represent just the limits of our measuring instruments.

      The UV catastrophe and Planck's quantum

      By the rise of electric power, towards the end of the 19th century, the question of what was more efficient, gas light or electric light, became economically important. To investigate efficiency scientifically, it was necessary to develop a standard light source with which the various types of light sources could be compared. In 1887, inspired by Werner von Siemens, a special state laboratory was established in Berlin - the Physikalische-Technische Reichsanstalt - for physical research on applications of electricity.

      The standard instrument for light intensity and color measurement, is basically a closed hollow cavity whose inner walls are heated to a precisely known temperature. The hot walls will start to emit and absorb heat radiation - infrared. When the temperature is further increased, visible light and even UV - ultraviolet light will be emitted. The intensity distribution of the emitted light, which is an EM spectrum, depends on the inside temperature of the walls.

      Since the cavity is closed the radiation cannot leave the box, therefore an equilibrium condition developes within the cavity. In 1859 Gustav Kirchhoff ^[14] (1824-1887) calculated on theoretical mathematical grounds that the intensity distribution over the EM spectrum of the radiation in that cavity does not depend on the nature of the material of the inner walls but only on their temperature. This independency of the wall material is highly suitable for the manufacture of an industry standard for light measurement. A small opening is made in the cavity wall sufficiently for measuring the radiation intensity СКАЧАТЬ