2014-12-12
Explanation
The Joke
A troll argues that if trolls are exposed to the sun, they die. Another character calls this "dumb." A scientist (a woman with glasses) explains the physics: a photon is not like a chair -- when a photon hits another photon and causes an emission, it is not the same photon. All photons are the same, so how would a troll body tell a sun photon from a photon reflected off the moon? Almost all photons leave the sun, make it through the atmosphere without "touching" anything, then hit the troll. The troll dismisses this as "just a fairytale that costs trolls a lot of quality work time" and insists "this is physics, jill, and I am telling you!"
In the final panel (labeled "Later"), someone asks: "Where did you get the awesome troll sculpture?" and the woman replies "Made it myself" -- implying she tricked the troll into standing in the sun by convincing it sunlight was safe, and it turned to stone.
The Humor
The comic plays on the classic fantasy trope that trolls turn to stone in sunlight. The humor comes from the inversion of science denial: instead of a person rejecting science, the troll rejects the physics explanation that would save its life. The troll dismisses actual photon physics as a "fairytale" and claims to know better -- mirroring how science deniers often reject expert knowledge in favor of their own beliefs. The dark punchline reveals the troll paid the ultimate price for its anti-intellectualism, having been turned to stone and now displayed as a sculpture.
References
The comic references the folklore tradition (popularized in J.R.R. Tolkien's works) that trolls turn to stone when exposed to sunlight. The physics explanation about photons is a simplified but accurate description of how photon emission and reflection work.