Frank Wilczek: Energy

“The result will be points of quiescence—technically known as nodes—where the air's density varies not at all, and no sound is heard. Note the paradox here: either sphere alone creates a sound wave at this point; two spheres together add up to no sound there at all. Two sources can add up to give less than one. This is the essence of destructive interference. (When two sources are giving the same instruction, the resulting vibration bears not twice but four times the energy. This phenomenon, oxymoronically known as constructive interference, may seem puzzling.)”

Frank Wilczek

Source: Longing for the Harmonies: Themes and Variations from Modern Physics (1987), Ch.12 Light as Waves

Time

“To understand this radiation [ cosmic microwave background ], it is easier to begin thinking about the radiation from a very hot gas like that inside a neon light. The same neon… is, at room temperature, utterly transparent… The character of matter in general changes abruptly when it gets heated above 3,000 degrees or so. Below this temperature, matter is electrically neutral… At high temperatures in a neon light, the electrically charged pieces of atoms become unstuck. Frequent and violent collisions break down neutral atoms into electrons and unbalanced nuclei. Matter in this state is called plasma, and it radiates much of its collision energy in the form of light. …a gas of neutral atoms (like air) is virtually transparent. The free [charged] nuclei and electrons of plasma, by contrast, couple to light's electromagnetic fields and absorb it very efficiently. …You …see light only from the borderline layer of neon between opaque plasma and transparent neutral atoms.”

Frank Wilczek

Longing for the Harmonies: Themes and Variations from Modern Physics (1987)

Understanding , Thinking , Light , Change

“E = mc2 really applies only to isolated bodies at rest. In general, when you have moving bodies, or interacting bodies, energy and mass aren't proportional. E = mc2 simply doesn't apply. …For moving bodies, the correct mass-energy equation is
E=\frac {mc^2} {\sqrt{1-\frac{v^2} {c^2}}}
where v is the velocity. For a body at rest (v=0), this becomes E = mc2. …we must consider the special case of particles with zero mass… examples include photons, color gluons, and gravitons. If we attempt to put m = 0 and v = c in our general mass-energy equation, both the numerator and denominator on the right-hand-side vanish, and we get the nonsensical relation E = 0/0. The correct result is that the energy of a photon can take any value. …The energy E of a photon is proportional to the frequency f of the light it represents. …they are related by the Planck-Einstein-Schrödinger equation E = hf, where h is Plank's constant.”

Frank Wilczek

when the velocity <math>v</math> approaches the speed of light c, the denominator approaches 0 thus E approaches infinity, unless m = 0.
Source: The Lightness of Being – Mass, Ether and the Unification of Forces (2008), Ch. 3, p. 19 & Appendix A

Color , Light

“In a sense, all of Earth glows in the dark. The energy release from natural radioactivity, the lingering fluorescence of stellar explosions, keeps Earth dynamic. It melts the core and keeps it flowing, and heats the crust and mantle, with consequences ranging from the generation of earth's magnetic field to earthquakes and the motion of continents. By contrast, Luna and Mars, because they are smaller, derive less energy from radioactive decays. Geologically, they are dead.”

Frank Wilczek

Source: Longing for the Harmonies: Themes and Variations from Modern Physics (1987), Ch.11 Explosions and Fluourescence (or, Entropy's Revenge)

Nature , Sense , Dead

“If grand unified theories are correct, we ought to be able to derive the relative power of the strong, weak, and electromagnetic interactions at accessible energies from their presumed equality at much higher energies. When this is attempted, a wonderful result emerges. …in the form first calculated by Howard Georgi, Helen Quinn, and Steven Weinberg …The couplings of strong-interaction gluons decrease, those of the [weak interaction] W bosons stay roughly constant, and those of the [electromagnetic interaction] photons increase at short distances [or high energies]—so they all tend to converge, as desired.”

Frank Wilczek

Longing for the Harmonies: Themes and Variations from Modern Physics (1987)

Strong

“Different ways of writing the same equation can suggest very different things, even if they are logically equivalent…. In Einstein's original 1905 paper, you do not find the equation E = mc2. What you find is m = E/c2…. the title of the paper is a question: "Does the Inertia of a Body Depend on Its Energy Content?" …If we can explain mass in terms of energy, we'll be improving our description of the world. We'll need fewer ingrediants in our world-recipe.”

Frank Wilczek

Source: The Lightness of Being – Mass, Ether and the Unification of Forces (2008), Ch. 3, p. 19.

World , Way , Question , Dependency

“Why can stars do better than the big bang? …During the big bang, there were only a few minutes when nuclei could form. Very rare processes, or slow ones, played little role. A case in point is the key process from which the sun derives its energy. In this reaction, two protons collide to produce a deuterium nucleus, a neutrino, and a positron. …This reaction belongs to the family of weak interactions. …It remains… a remarkable—and for humanity, remarkably fortunate—circumstance that the central reaction that drives the sun is so rare. It is only this extraordinary rarity that allows the average proton in the sun to last so long, billions of years, even though it is colliding with other protons millions of times a second. …an entertaining example of Treiman's theorem.”

Frank Wilczek

Longing for the Harmonies: Themes and Variations from Modern Physics (1987)

Family , Star , Time , Sun

“What is conserved, in modern physics, is not any particular substance or material but only much more abstract entities such as energy, momentum, and electric charge. The permanent aspects of reality are not particular materials or structures but rather the possible forms of structures and the rules for their transformation.”

Frank Wilczek

Source: Longing for the Harmonies: Themes and Variations from Modern Physics (1987), Ch.8 The Weak Interaction

Reality