Heuristics

Discovering order through models that account for unobserved behavior but can detect unimaginably small entities.

atomic nuclei | spectrum | light | science & uncertainty

The case of light-quantum mechanics.

What is light?

A prism is a triangular shaped glass solid that refracts, or bends light in a way that generates a pattern, reminiscent of the way colors align in a row.

Newton used a prism to inspect the properties of light.The outcome of his experiments were remarkably similar to the pattern or bands of light in the array of pigments observable in a raindow.The pattern is red, orange, yellow, green, blue, indigo and violet. Based on the work of Neils Bohr, who interpreted the frequencies of light, there is a direct relation between the energy surrounding any atom and the frequency of emissions (electromagnetic radiation) from the nuclei and surrounding electron shells.

	Three quarks make up neutrons and neutrons are part of massive atomic nuclei.
	Neutrons (red) carry no charge, [ ø ]. Protons (blue) are positively charged [ + ].

A model of the Atomic Nuclei

Massive subatomic particles:

Protons determine the chemical property of atomic element: H, Hydrogen nuclei possess one proton, whereas He, Helium is comprised of two protons.

As the Encyclopedia Britannica suggests, " The nucleus of ordinary hydrogen is an isolated proton, but the isotope deuterium has a neutron bound to the proton. Both of these isotopes are stable. The third hydrogen isotope, tritium, has two neutrons and is radioactive. Radioactive isotopes can be made for many elements; the more the number of neutrons deviates from the optimum number for that atomic mass, the shorter the life of the radioactive isotope." [Atom; Atomic mass number]

All elements can be distinguished from one another by the absorption of light and thus each atomic element has a distinguishing pattern based on its absorption spectrum.

Before 1911, Neils Bohr had understood that light and radiation were means of seeing into a very strange world of particle physics.

"Glowing hydrogen, like other elements, emits a distinctive series of spectral lines. To get spectral lines Bohr realized he must allow the electron to have the option of a number of different orbits (clouds enshrouding the nuclei) corresponding to different energy contents. So he gave hydrogen's single electron a set of allowed radii representing a set of states of higher and higher energy."

"... radiation occurs when an electron 'jumps' from one energy level to a lower one; the energy of the radiating photon is the difference of the two energy levels."

"Bohr...was, in the words of Einstein, trying to know the mind of God"

Einstein insisted that God does not play dice with the universe with respect to quantum probability.

(Leon Lederman, The God Particle, "The Naked Atom," pp. 159-160. )

Einstein

---

Light is the means by which we may begin to understand the mystery of the world which we can not see, touch, or in any real way to sense.

The speed of light has become a measure of the world we inhabit, called since Einstein, spacetime, because he recognized time as embedded in the contours of outer space. The barrier is 300,000 meters or 186,000 miles per second, the velocity at which photons travel. At that barrier time slows, leading to the paradoxical concept that anything capable of moving faster than the velocity of light moves backwards in time. Or antimatter can be conceived of, according to Richard Feynman as either substances made of oppositely charged subatomic particles, or subatomic particles like electrons and protons traveling backwards in time.

Richard Feynman,  QED:  The strange theory of light and matter.

“. . .while I am describing to you how Nature works, you won’t understand why nature works that way.  But you see  nobody understands that (why nature works).  I can’t explain why Nature behaves in this peculiar way.”

[p 10]

“the essential question.  Rather, . . .is whether or not the theory gives predictions that agree with experiment.”

“The theory of quantum electrodynamics describes nature as absurd from the point of view of common sense.  and it agrees fully with experiment.  So I hope you can accept Nature as she is -- absurd.”

“The human eye is a very good instrument:  it takes only about five or six photons to activate a nerve cell and send a message to the brain.  If we evolved a little further so we could see ten times more sensitively, we wouldn’t have to have this discussion -- we would all have seen very dim light of one color as a series of intermittent little flashes of equal intensity.”   [photons] 

[p. 14]

“When I say “light” in these lectures, I don’t mean simply the light we can see from red to blue.  It turns out that visible light is just a part of a long scale that’s analogous to the musical scale in which there are notes higher than you can hear and other notes lower than you can hear.  The scale of light can be described by numbers --called the frequency-- and as the numbers get higher, the light goes from red to blue to violet to ultraviolet.  We can’t see ultra-violet light, but it can affect photographic plates.  It’s still light --only the number is different.  (We shouldn’t be so provincial: what we can detect directly with our own instrument, the eye, isn’t the only thing in the world!)  If we continue to simply to change the number, we go out into X-rays, gamma rays, and so on.  If we change the number in the other direction, we go from blue to red to infrared (heat) waves, then television waves, and radio waves.  For me all of that is ‘light.’  I’m going to use just red light for most of my examples, but the theory of quantum electro-dynamics extends over the entire range I have described, and is the theory behind all these various phenomena.”

[pp. 13-14]

“In these lectures I want to tell you about the part of physics I know best, the interaction of light and electrons.  Most of the phenomena you are familiar with involve the interaction of light and electrons -- all of the chemistry and biology . . . .”  The only phenomena that are not covered by this theory are the phenomena of gravitation and nuclear phenomena;  everything else is contained in this theory.”

[p. 77]

Richard Feynman,  QED:  The strange theory of light and matter, (Princeton: Princeton University Press: 1987).

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