Planck and Radiant Energy

The gradual emergence of quantum mechanics was occasioned by a series of questions revolving around radiation - how energy is emitted by material objects. The energy can be in the form of heat, light, or other electromagnetic waves, or in the form of particles.

Physicists worked to find mathematical models which could predict when and how such energy would be emitted. Roger Stuewer writes:

In 1859–60 Kirchhoff had defined a blackbody as an object that reemits all of the radiant energy incident upon it; i.e., it is a perfect emitter and absorber of radiation. There was, therefore, something absolute about blackbody radiation, and by the 1890s various experimental and theoretical attempts had been made to determine its spectral energy distribution — the curve displaying how much radiant energy is emitted at different frequencies for a given temperature of the blackbody. Planck was particularly attracted to the formula found in 1896 by his colleague Wilhelm Wien at the Physikalisch-Technische Reichsanstalt (PTR) in Berlin-Charlottenburg, and he subsequently made a series of attempts to derive “Wien’s law” on the basis of the second law of thermodynamics. By October 1900, however, other colleagues at the PTR, the experimentalists Otto Richard Lummer, Ernst Pringsheim, Heinrich Rubens, and Ferdinand Kurlbaum, had found definite indications that Wien’s law, while valid at high frequencies, broke down completely at low frequencies.

The work of Kurlbaum and Rubens provided the impetus and raw material for Planck’s discovery of a new law. Kurlbaum was born in 1857 and had been working in Berlin since 1891. Rubens was born in 1865, and was working in Berlin by 1888 or possibly earlier.

Kurlbaum died in 1927, and Rubens in 1922. The latter’s death may have been the result of exposure to high levels of radiation from working with radium and other unstable isotopes in a laboratory. The dangers of such radiation to human health had not yet been fully understood at that time.

The work of Kurlbaum and Rubens provided data from which Planck could construct, and then test, a mathematical model of energy emission. Werner Heisenberg describes how Planck came to make a discovery:

Als Planck im Jahre 1895 mit seiner wissenschaftlichen Arbeit in dieses Forschungsgebiet eintrat, versuchte er das Problem von der Strahlung auf das strahlende Atom zu verschieben. Durch diese Verschiebung wurden die tieferen Schwierigkeiten des Problems zwar nicht beseitigt, aber ihre Interpretation und die Deutung der empirischen Tatsachen wurden dadurch einfacher. Eben in jener Zeit, nämlich im Sommer 1900, hatten Curlbaum und Rubens in Berlin sehr genaue Messungen des Spektrums der Wärmestrahlung vorgenommen. Als Planck von diesen Ergebnissen hörte, versuchte er sie durch einfache mathematische Formeln darzustellen, die nach seinen allgemeinen Untersuchungen über den Zusammenhang zwischen Wärme und Strahlungen plausibel aussahen. Eines Tages, so wird berichtet, trafen sich Planck und Rubens in Plancks Hause zum Tee und verglichen Rubens’ neueste Resultate mit einer Formel, die Planck zur Deutung von Rubens’ Messungen vorgeschlagen hatte. Der Vergleich zeigte eine vollständige Übereinstimmung. Damit war das Plancksche Gesetz der Wärmestrahlung entdeckt.

Planck’s discovery was not the end, but rather the beginning of a series of discoveries which would together constitute a major revision of hypotheses about radiant energy. The task of systematizing or predicting the emission of energy from matter, and more specifically from an atom, would prove to be the puzzle which occasioned the emergence of quantum physics and the fabled discoveries made by Heisenberg.

The Riddle of Energy and Matter

The common phenomenon of material which glows when heated offers complex challenges to physics. Although common, it is by no means easy to explain why a certain substance emits light of a certain color when it is heated to a certain temperature.

One commonly sees iron glowing from red to yellow when heated by a blacksmith. But why red or yellow? Why not blue or green? And why precisely this color at this temperature?

One of the physicists who investigated this question is John William Strutt, better known as Baron Rayleigh, and more properly, known as the 3rd Baron Rayleigh, to distinguish him from his father and from his son. Wrestling with various questions in physics, he wrote:

I have never thought the materialist view possible, and I look to a power beyond what we see, and to a life in which we may at least hope to take part.

His son, Robert Strutt, worked on similar problems, and is known as the 4th Baron Rayleigh. His work showed that the questions about light emitted from heated matter are related to questions about light emitted from matter through which an electric current moves.

Where Rayleigh left off, James Hopwood Jeans began, and formulated the Rayleigh-Jeans law. This formula, based on classical mechanics, approximates the observations of emitted radiation from a body for a certain range of values, but deviates substantially from empirical data for values above and below that range.

The failure of the Rayleigh-Jeans law was one, of several, impetuses for the development of quantum mechanics. Werner Heisenberg writes:

Der Anfang der Quantentheorie ist mit einem bekannten Phänomen verbunden, das keineswegs zu den zentralen Teilen der Atomphysik gehört. Irgendein Stück Materie, das erhitzt wird, beginnt zu glühen, es wir rot- oder schließlich weißglühend bei hohen Temperaturen. Die Farbe hängt nicht sehr stark von der Oberfläche des Materials ab, und für einen schwarzen Körper hängt sie sogar allein von der Temperatur ab. Daher ist die Strahlung, die durch solch einen schwarzen Körper bei hohen Temperaturen ausgesandt wird, ein geeignetes Objekt für physikalische Untersuchungen. Da es sich um ein einfaches Phänomen handelt, sollte es auch auf Grund der bekannten Gesetze der Strahlung und der Wärme eine einfache Erklärung dafür geben. Der Versuch zu einer solchen Erklärung, der gegen Ende des 19. Jahrhunderts durch Rayleigh and Jeans gemacht wurde, brachte jedoch sehr ernste Schwierigkeiten an den Tag. Es ist leider nicht möglich, diese Schwierigkeiten in einfachen Begriffen zu beschreiben. Es muß genügen festzustellen, daß die folgerichtige Anwendung der damals bekannten Naturgesetze nicht zu sinnvollen Resultaten führte.

The failure of the Rayleigh-Jeans law nudged physicists, including Max Planck, to look at the micro level, to look at the atom, for clues about the mechanisms which predict or determine the amount of energy matter will release, the wavelength and direction of that energy, and how that release of energy is determined by the temperature to which the matter is heated, or by the amount and type of electric current which is sent through it.

Thus the riddle presented by the Rayleigh-Jeans law reaches to the central questions of quantum mechanics, and to the legendary results of Heisenberg.

Concerning the Impossibility of Gender Reassignment

The phrases “gender reassignment” and “sex change” appear increasingly in contemporary discourse. While speakers believe that they have some intuitive meaning for these terms, a rigorous definition is a complex task.

Geneticists, biologists, anatomists, and other empirical and observational scientists work with the distinction between male and female, and need functional decision procedures to determine gender. Likewise, the legal system has the same need to distinguish between the two, but does so in a different way. Finally, the business world has a need to make the gender distinction, but does so in a third way.

An interesting moment occurs when the empirical scientist, the lawyer, and the businessman must find verbal formulations which satisfy all three of them.

An enterprise called the Genographic Project, organized by the National Geographic Society, is such an instance. Offering some form of genetic analysis to the public, the project involves geneticists. Because it is a non-profit commercial enterprise, it includes business leaders who want to make sure that it is financially viable, and they hire lawyers to protect those revenues from potential lawsuits.

Such genetic analysis is gender-dependent. The way the test results are processed and interpreted depends upon the gender of the donor. In this context, then, the question must be posed to the person donating the sample (usually saliva): “what is your gender?”

The answer, for the purposes of genetic analysis, is an answer that cannot be changed by gender reassignment surgery, by various hormone treatments, or by any other form of gender reassignment therapy. A geneticist analyzes a sample from an individual based on an immutable gender identity which that individual received before birth.

Moving from science to law, the legal disclaimers on the materials and genetic sampling kits distributed by the Genographic Project are designed to clearly inform the individual who donates a sample, and designed to avoid lawsuits which could arise from misunderstandings. These disclaimers state:

Because women do not carry a Y chromosome, this test will not reveal direct paternal deep ancestry for female participants. Women will learn other information about their paternal side of the family, however.

In the same document, the following statement reiterates the clear and immutable gender difference:

We will run a comprehensive analysis to identify thousands of genetic markers on your mitochondrial DNA, which is passed down each generation from mother to child, to reveal your direct maternal deep ancestry. For men, we will also examine markers on the Y chromosome, which is passed down from father to son, to reveal your direct paternal deep ancestry.

When a patient, or donor of genetic material, submits a sample to a geneticist, the geneticist has no choice to but to analyze the sample as being given by a person of the gender which the donor had at conception and at birth. No gender reassignment surgery or therapy can change the donor’s gender identity. The laboratory is indifferent to whether the donor “identifies as” a male or female.