The Physics of Superheroes: Spectacular Second Edition (40 page)

Likewise, the electron is held in an orbit by its electrostatic attraction to the positively charged nucleus. If “plucked” in the right way, a matter-wave for the bound electron can take on a higher energy value. When the electron then relaxes back to its lower fundamental frequency, it must do so by making a discrete jump. Energy is conserved; consequently, the electron can only lower its energy when returning to the lower frequency level by giving off a packet of energy equal to the difference between its higher energy level and the lower level it is relaxing to. Because the energies available to the electron are discrete, well-defined values similar to the overtones possible for a clamped string, this jumping from one energy state to another is termed a “quantum transition” or a “quantum jump.” The discrete packet of energy given off by the electron when making this transition is typically in the form of light, and a quantum of light energy is termed a “photon” (a concept introduced by Albert Einstein, again in 1905—a busy year for him and physics—though the term “photon” was not coined until 1926 by Gilbert Lewis).

If a glass tube is filled with a gas such as neon, and an electrical current is passed through the gas, the energetic electrons of the current will sometimes collide with the neon atoms. When the energy of the energetic electrons is just right, the neon atoms can be excited into a higher energy state. After the collision, the excited neon atoms will relax back to their original lower energy configuration, emitting a photon of light that has the frequency (hence, color) that corresponds to the energy difference between its starting and final states. This is why neon lights have their identifiable color. By changing the type of gas in the tube, different colors of light can be selected. You could do this with any gas, but only certain elements have a transition within the visible portion of the light spectrum. If the atoms suffer highly energetic collisions, such that many higher energy states are excited, then many discrete wavelengths of light will be given off when the different overtones all relax back to the fundamental level. Different elements have differing arrays of overtones and fundamental frequencies, just as different strings on a violin or guitar will have different vibrational modes depending on the length, width, and tension. Two identical violin strings clamped with the same tension will have the same range of possible frequencies when plucked. Similarly, two identical atoms will have the same spectrum of emitted light when they relax from an excited state.

In this way, the spectrum of wavelengths of light emitted by an energetic atom is unique and can be considered the fingerprint of the particular element. The lighter-than-air element helium was discovered by the detection of its characteristic spectrum of light coming from the sun (the word “helium” is derived from Helios, the Greek sun god). By careful comparison with the spectrum of light emitted by hydrogen and other gases, scientists concluded that this array of wavelengths must arise from a new element that at the time had never been found terrestrially. Fortunately for the Macy’s Thanksgiving Day Parade, underground pockets of helium were eventually discovered.

The notion that there is a wave associated with the motion of any object, and that the wavelength of this wave is inversely proportional to its momentum, is weird, but by accepting this mysterious concept, we gain an understanding for the basis of all of chemistry. Bring two atoms close enough together, and they may form a chemical bond, and in so doing create a new basic unit, the molecule. Why would the atoms do this? The negatively charged electrons in the first atom certainly will repel the negatively charged electrons in the second atom. Before quantum mechanics, there was no satisfactory fundamental explanation for why the universe didn’t just consist of isolated elemental atoms.

The driving force underlying the bonding between atoms is the interactions of the matter-waves of the electrons from the different atoms. When the two atoms are held very far apart, the matter-waves of the atomic electrons do not overlap. When the atoms are brought close enough together so that the electron clouds around each atom intersect, the electronic matter-waves from each atom begin to interfere, forming a new wave pattern, just as two stones tossed into a pond create an intricate pattern of ripples that is very different from the pattern that would be created by each stone separately. In most cases this new pattern is a high-energy, discordant mess, similar to the sound resulting from a clarinet and violin played simultaneously by novices with no musical training or talent. In these cases, the two atoms do not form a chemical bond and do not chemically interact. In a few special cases, the two matter-waves interact harmoniously, creating a new wave pattern that has a lower-energy configuration than the two separate matter-waves. In these special cases, the two atoms can lower their total energy by allowing the matter-waves to interact in this manner, and once in a lower-energy state, it requires the addition of energy (called the “binding energy” or “bonding energy”) to physically separate them. In this way, despite the considerable repulsion between the negatively charged electrons, the two atoms are held together in a chemical bond, owing to the wave-like nature of the electrons.

These arguments about discrete energy levels in an atom arising from those particular orbits that correspond to an integral number of wavelengths of the electron matter-wave seem so reasonable that it’s a shame that they’re not really correct. The electron cannot literally be considered to move in a circular or elliptical orbit around the positively charged nucleus, despite the appealing analogy to our solar system. For one thing, the electron would be constantly accelerated as it bends onto a curved path. As argued in the previous chapter, an accelerating electric charge emits electromagnetic waves that carry energy, so if the electron continuously radiates light in its orbit, it would lose kinetic energy. Eventually, the electron should spiral into the nucleus in a little less than a trillionth of a second, so no elements should be stable, and hence there would be no chemistry and no anything if the electrons really moved in curved orbits.

Nevertheless, the notion that only certain wavelengths are allowed, with corresponding discrete energy levels, is still a valid one, even if the picture we employed to get there can only be considered a useful metaphor and not a literal description. Instead of thinking of the electron as a point particle that moves in a circular orbit with a particular matter-wave associated with it, the full quantum theory of Heisenberg and Schrödinger, to be discussed in the next chapter, tells us that there is a “wave function” for the electron. For a plucked violin string, it makes no sense to ask at what position on the string the wave is. Similarly for the electron in an atom, its matter-wave extends over the atom, and we cannot specify the electron’s position or trajectory more accurately than this. Electrons only emit or absorb light when moving from one wave pattern to another in the atom. As we’ll see in the next chapter, these matter-waves are also responsible for a crisis on infinite Earths!

22

NOT A DREAM! NOT A HOAX! NOT AN
IMAGINARY TALE!—
QUANTUM MECHANICS

THE ORIGIN TALE in
Showcase # 4
describing how Barry Allen gained his superspeed powers and became the Silver Age Flash featured a symbolic passing of the torch from the earlier Golden Age of superheroes. Just prior to being struck by the lightning bolt that simultaneously doused him with exotic chemicals, and that naturally would enable him to run at the speed of light, police scientist Allen relaxed with a milk-and-pie break in his lab while reading
Flash Comics # 13,
featuring the Golden Age Flash on its cover. After the freak accident gave Barry his superpowers, his immediate thoughts turned to how he could use his superspeed to help humanity. Taking his inspiration from the Flash comic book he had been reading before he was struck by lightning, he donned a red-and-yellow costume and began his crime-fighting career as the Silver Age Flash (though he referred to himself simply as the Flash, not realizing that he was himself a comic-book character in the dawning Silver Age of superheroes). In a turn of events that nowadays would be described as “postmodern,” and back then was simply considered “pretty neat,” it was established in the Flash comic books of the 1960s that the Flash character of the 1940s (who wore a different costume and gained his superspeed in a different, though equally implausible, chemical accident) was a comic-book character in Barry Allen’s “reality.”

The Golden Age Flash (whose secret identity was Jay Garrick) was considered fictional, as far as the Silver Age Flash was concerned, until September 1961. That month saw the publication of the classic story “Flash of Two Worlds” in
The Flash # 123
(fig. 30), where it was revealed that the Silver Age Flash and the Golden Age Flash both existed, but on parallel Earths, separated by a “vibrational barrier.” In this story, the Silver Age (Barry Allen) Flash accidentally vibrated at superspeed at the exact frequency necessary to cross over to the Earth on which his idol, the Golden Age (Jay Garrick) Flash, lived. Once he realized that he was in the world of the Golden Age heroes, Barry met Jay and introduced himself. “As you know,” the police scientist explained, “two objects can occupy the same space and time—if they vibrate at different speeds!” Apparently Barry Allen was a better forensic scientist than he was a theoretical physicist. Regardless of their vibrational frequency (and as we saw in Section 2, atoms in a solid do vibrate simply because they have some finite temperature), there is no way that two objects can be in the same place in space and time (unless we are discussing massless quantities such as light photons).

Fig. 30.
The cover to
The Flash # 123,
giving comic-book fans their first hint that there were at least two worlds beyond their own.

The writer of the “Flash of Two Worlds” story was Gardner Fox, who had also written many of the Golden Age Flash comics. He proposed a mechanism to explain how the Silver Age Flash could read comic books featuring the Golden Age Flash on this second Earth, while simultaneously providing insight into his work habits. As Barry hypothesized, “A writer named Gardner Fox wrote about your adventures—which he claimed came to him in dreams! Obviously when Fox was asleep, his mind was ‘tuned in’ on your vibratory Earth! That explains how he ‘dreamed up’ the Flash!”
⁷⁰
This crossover meeting between the Silver Age and Golden Age Flash was a hit with comic-book fans, and the Silver Age Flash would more and more frequently cross the vibrational barrier to Earth-2. (The world on which the Golden Age Flash resided, though it appeared first chronologically, was labeled Earth-2, while the world of the Silver Age was designated Earth-1. Our world, Fearless Reader, in which all superheroes exist solely as fictional characters in comic books, is called Earth-Prime.) Eventually, the Silver Age Justice League of America of the 1960s, consisting of the Flash, Green Lantern, the Atom, Batman, Superman, Wonder Woman, and other superheroes, met and had an adventure with Earth-2’s Justice Society of America from the 1940s, whose membership contained the Flash, Green Lantern, the Atom, Batman, Superman, Wonder Woman, and others. So popular was this meeting of the two superteams, that it quickly became an annual tradition. But the Justice League and Justice Society could visit each other’s Earth only so many times before the novelty wore off. Soon the Justice League branched out and visited other Earths, such as Earth-3, where the evil analog of the Justice League of America had formed the Crime Syndicate of America (presumably to distinguish themselves from their European criminal counterpart). Captain Marvel—that is, Billy Batson, who could become a superhero by shouting “Shazam!”—and the rest of his supporting cast inhabited Earth-S, and were in due time paid a crossover visit by the Justice League of America.
⁷¹
Earth-X, Earth-4, and others soon followed, and eventually the phrase “multiverse” became appropriate to describe the seemingly endless number of alternate universes that abounded.

The issues of the Justice League of America that describe the meeting of the Silver and Golden Age heroes always carried titles such as “Crisis on Earth-2” or “Crisis on Earth-X.” The story lines eventually became so convoluted, with so much alternate history to keep straight, that in 1985, DC Comics attempted to normalize the multiverse. The yearlong miniseries describing this simplification process was called “Crisis on Infinite Earths.” With a vast housecleaning of continuity under way, the writers and editors at DC Comics used this opportunity to weed out poor sellers from many of the less-popular worlds and bring all the heroes from the better-selling titles together on one Earth (coincidentally, the Earth -1 of the Silver Age heroes). Consequently, the “Crisis on Infinite Earths” miniseries is noteworthy to comic-book fans for the deaths of the Barry Allen Flash and Supergirl (both of whom died heroic deaths struggling against the evil tyrant who threatened to destroy the Silver Age Earth-1) and the removal of Superboy from Superman’s history. Unlike most comic-book fatalities, both Barry Allen and Supergirl have remained dead for the most part (though they have both returned to continuity between the writing of the first and second editions of this book), while crime-fighting adventures have begun to creep back into Clark Kent’s teen years once again.