Friday Sprog Blogging: a song with secret science content?

This week, in SprogCast #4, the younger Free-Ride offspring sings and then suggests that the song bears on the planetary subject of the very first Friday Sprog Blogging entry, which also involved singing.
You can download the sound file for the a cappella performance and the discussion that follows. The transcript is included below.

The song is the Jonathan Coulton composition, I’m Your Moon. The younger Free-Ride offspring sang the first verse and the chorus.

They invented a reason
That’s why it stings
They don’t think you matter
Because you don’t have pretty rings
I keep telling you I don’t care
I keep saying there’s one thing they can’t change
I’m your moon
You’re my moon
We go round and round
From out here, it’s the rest of the world that looks so small
Promise me
You will always remember who you are

Dr. Free-Ride: So what do you think that song is about?
Younger offspring: I think it’s about Pluto getting … devoted?
Dr. Free-Ride: Demoted?
Younger offspring: Demoted.
Dr. Free-Ride: Uh huh. From being a planet like the other planets to being a pluton.
Younger offspring: Yeah. What is a pluton?
Dr. Free-Ride: A pluton is … not one of the planets that we count as a planet. It’s sort of a lesser planet.
Younger offspring: Like a planet too small to be a planet?
Dr. Free-Ride: Yeah, size has something to do with it, and what kind of orbit it has relative to the other planets has something to do with it. So. So maybe you think it’s a song sung sort of from the point of view of Pluto’s moon?
Younger offspring: Mmm hmm.
Dr. Free-Ride: Saying, “Who cares what the International Astronomical Union says. You’re still here. You’re still going around me. I’m still going around you. We’re still out here. We can still sort of see the sun, very far away.”
Younger offspring: So the moon is singing the song and the moon is talking to Pluto.
Dr. Free-Ride: Well, but not Earth’s moon, Pluto’s moon.
Younger offspring: That’s what I meant, Pluto’s moon!
Dr. Free-Ride: I think it’s Pluto’s moon, reassuring Pluto — if indeed it’s a song about Pluto. Although I can’t really tell. Authorial intent is difficult to read sometimes.
Younger offspring: I can. But, does Pluto really sting? Because the song said, “that’s why it stings”.
Dr. Free-Ride: I think what stings is the decision that Pluto’s not really a planet. So it hurts — it hurts Pluto’s feelings. It stings.
Younger offspring: Uh.
Dr. Free-Ride: I think he was looking for a word that meant hurt that rhymed with rings.
Younger offspring: Oh. ‘Cause he was still thinking for … um … like, second line, when he’d already got the third and fourth line?
Dr. Free-Ride: Sometimes it happens that way.