fun-fact
Explanation
The Joke
A child eagerly asks a parent, "Hey! Wanna hear a fun fact about space?" The parent says "Sure!" The parent then says, in an aggressive tone: "On one of the rocky planets in the solar system, if you don't clean your room I smash your laptop into tiny pieces!" The caption at the bottom reads: "Fun Fact: Technically, all fun facts are space fun facts."
The comic sets up the expectation of a genuine astronomy fun fact -- something about planets, stars, or the cosmos. Instead, the parent hijacks the format to deliver a parenting threat, technically framed as a fact about "one of the rocky planets in the solar system" (i.e., Earth). The caption then drives the pedantic point home: since everything happens in space and Earth is a planet in space, any fact about anything is technically a "space fun fact."
The Humor
The humor works through the bait-and-switch of the child's innocent enthusiasm being met with the parent's creative repackaging of a threat as an astronomical observation. The parent is being technically correct -- Earth is indeed a rocky planet in the solar system -- while completely subverting the spirit of the child's question. The bottom caption elevates the joke from a simple parenting gag to a broader philosophical observation about the arbitrary boundaries we draw around categories of knowledge.