The implication is that after a night of carousing, his wife has propelled a lamp toward him at near light speed, but the date is both unnecessary and unfortunate. At this point in time, Elsa Einstein was already seriously ill with the disease(s) that killed her in December 1936.
Re: Kilby: Maybe not “at near light speed.” Any speed that a light is thrown is by definition “the speed of light.”
@ Pinny – That is true for light, but she threw only the lamp: the lamp is throwing the light. Paradoxes involving light sources moving at various fractions of the speed of light are among the most confusing (but also the most entertaining) aspects of having to endure physics lectures about Einstein’s poorly named “Relativity” theory.
Also, he didn’t have the characteristic white hair in 1936. (His first wife did definitely have good motivation to hurl a lamp at him, though.)
That date is doubly unfortunate as, in the USA, September 11 is as iconic as December 7.
I was going with the idea that the cartoonist was humorously using the word “light” to mean “lamp” or “light bulb”, i.e., the source of the light rays, rather than the rays themselves. This would be similar to the colloquial use of the phrase, “Please turn on the light,” when we mean “Please switch on the lamp.” Another example would be the term “nightlight.” We use it to refer to the bulb-and-switch-contraption — not to the to the rays that emanate from the bulb.
The joke depends on the fact that people often call a lamp a “light.” The “speed of light” here does refer to the speed of the lamp.
I agree that here “speed of light” = “speed of lamp,” but I’m still not seeing a joke here. I joke needs more than “Hey, did you know some words have more than one meaning?”
Arthur: I suspect September 11th is much more iconic than December 7th.
Clever title for this one.
The joke depends on the fact that people often call a lamp a “light.”
That was the germ of one of the jokes in “Airplane”. “Steve, I want every light you can get poured onto that field.”
“Clever title for this one.”
Or maybe C++ for programmers, C+ for students.
I agree, Winter: “September 11” doesn’t require any description beyond the date itself.
I can think of only “4th of July” that shares this.
I always wondered: is it a coincidence that the constant C in that equation just happens to equal the speed of light in a vacuum, or is there a fundamental reason for it that ties the relationship of mass and energy with the limit on signal propagation?
@Mark in Boston, it’s fundamental. The speed of light is dependent on more fundamental characteristics (I believe one is the permitivity of space), which are among the fundamental constants of nature.
Mark in Boston: If you take a course or read a textbook on special relativity, it will eventually work its way from “c, the speed of light is the same in any inertial reference frame” to E=mc^2.
@Mark in Boston — the way I’ve always thought of it is that c is the speed of reality. The fact of an event propagates outward at c. There isn’t a universal clock that gives a single “now” across reality — instead, “now-ness” propagates. From the point of view of a thing traveling at c, time isn’t passing, because it is just coasting along at the speed of reality, so “now” isn’t passing it. It’s just staying in the same “now”, because it’s travelling right along with “now.” So the photon is just traveling at the speed of reality, without time passing for it.
That’s weird. So a photon is thus truly dimensionless? It has no height, width, depth or duration? From its own point of view, it exists only at a point in time? This means that a photon cannot change to a different energy state, because change takes time. It can be absorbed by an atom and another photon with different energy emitted. That second photon can then be absorbed by another atom; it dies at the instant it is born.
@ MiB – “…It can be absorbed by an atom and another photon with different energy emitted…”
That only works if the electron configuration of the absorbing atom has another (intermediate) energy level that permits a smaller quantum jump back down.
@Mark in Boston, that’s essentially right. I’d say “particle” rather than “atom” (photons interact with anything that has a charge, e. g. muons), and “interact” rather than “be absorbed,” but that’s nitpicking. Which is my specialty.
Comics I Don't Understand 
The implication is that after a night of carousing, his wife has propelled a lamp toward him at near light speed, but the date is both unnecessary and unfortunate. At this point in time, Elsa Einstein was already seriously ill with the disease(s) that killed her in December 1936.
Re: Kilby: Maybe not “at near light speed.” Any speed that a light is thrown is by definition “the speed of light.”
@ Pinny – That is true for light, but she threw only the lamp: the lamp is throwing the light. Paradoxes involving light sources moving at various fractions of the speed of light are among the most confusing (but also the most entertaining) aspects of having to endure physics lectures about Einstein’s poorly named “Relativity” theory.
Also, he didn’t have the characteristic white hair in 1936. (His first wife did definitely have good motivation to hurl a lamp at him, though.)
That date is doubly unfortunate as, in the USA, September 11 is as iconic as December 7.
I was going with the idea that the cartoonist was humorously using the word “light” to mean “lamp” or “light bulb”, i.e., the source of the light rays, rather than the rays themselves. This would be similar to the colloquial use of the phrase, “Please turn on the light,” when we mean “Please switch on the lamp.” Another example would be the term “nightlight.” We use it to refer to the bulb-and-switch-contraption — not to the to the rays that emanate from the bulb.
The joke depends on the fact that people often call a lamp a “light.” The “speed of light” here does refer to the speed of the lamp.
I agree that here “speed of light” = “speed of lamp,” but I’m still not seeing a joke here. I joke needs more than “Hey, did you know some words have more than one meaning?”
Arthur: I suspect September 11th is much more iconic than December 7th.
Clever title for this one.
The joke depends on the fact that people often call a lamp a “light.”
That was the germ of one of the jokes in “Airplane”. “Steve, I want every light you can get poured onto that field.”
“Clever title for this one.”
Or maybe C++ for programmers, C+ for students.
I agree, Winter: “September 11” doesn’t require any description beyond the date itself.
I can think of only “4th of July” that shares this.
I always wondered: is it a coincidence that the constant C in that equation just happens to equal the speed of light in a vacuum, or is there a fundamental reason for it that ties the relationship of mass and energy with the limit on signal propagation?
@Mark in Boston, it’s fundamental. The speed of light is dependent on more fundamental characteristics (I believe one is the permitivity of space), which are among the fundamental constants of nature.
Mark in Boston: If you take a course or read a textbook on special relativity, it will eventually work its way from “c, the speed of light is the same in any inertial reference frame” to E=mc^2.
@Mark in Boston — the way I’ve always thought of it is that c is the speed of reality. The fact of an event propagates outward at c. There isn’t a universal clock that gives a single “now” across reality — instead, “now-ness” propagates. From the point of view of a thing traveling at c, time isn’t passing, because it is just coasting along at the speed of reality, so “now” isn’t passing it. It’s just staying in the same “now”, because it’s travelling right along with “now.” So the photon is just traveling at the speed of reality, without time passing for it.
That’s weird. So a photon is thus truly dimensionless? It has no height, width, depth or duration? From its own point of view, it exists only at a point in time? This means that a photon cannot change to a different energy state, because change takes time. It can be absorbed by an atom and another photon with different energy emitted. That second photon can then be absorbed by another atom; it dies at the instant it is born.
@ MiB – “…It can be absorbed by an atom and another photon with different energy emitted…”
That only works if the electron configuration of the absorbing atom has another (intermediate) energy level that permits a smaller quantum jump back down.
@Mark in Boston, that’s essentially right. I’d say “particle” rather than “atom” (photons interact with anything that has a charge, e. g. muons), and “interact” rather than “be absorbed,” but that’s nitpicking. Which is my specialty.