Plutoid
Explanation
The Joke
A student asks a scientist, "Dear Science, why did you reclassify Pluto as a dwarf planet?" The scientist explains that Pluto is large like a planet, orbits the sun like a planet, but it doesn't meet the criterion of having "cleared its orbit of other objects." He goes on to explain that if we let Pluto be a planet, the solar system would have many more discovered (and lots of possible mystery) planets in every direction. The student responds: "Earth would be bad." The scientist replies, "This is why all those guys on the radio hate you."
The Humor
The comic addresses the perennial public outcry over Pluto's reclassification as a dwarf planet in 2006 by the International Astronomical Union. The scientist patiently explains the legitimate scientific reasoning — Pluto hasn't cleared its orbital neighborhood, and if we relaxed the criteria, we'd have to classify many other Kuiper Belt objects as planets too, making the category unwieldy.
The student's response ("Earth would be bad") is a non sequitur that ignores the careful scientific explanation, humorously representing the segment of the public that is emotionally attached to Pluto's planet status without engaging with the actual astronomy. The final panel's reference to "guys on the radio" jokes about how scientific illiteracy and emotional reasoning are amplified in popular media, where hosts often side with the sentimental "Pluto is a planet" camp rather than the scientific rationale.