Several times upon looking at the moon, I've always been inclined say that it is a planet in its own right. In fact I did say it on twitter. And by a slip of the twit-thumb, I've also mistakenly referred to exomoons as planets.
The allure of considering moons as planets is inescapable. Many scientists even describe Titan as "similar" to Earth! Another moon called Io was even singled out to describe an exoplanet by introducing a new type of planet called "Super-Io"!
Perhaps the inherent planet-like qualities of moons is the reason why the principal investigator on the New Horizons mission to Pluto couldn't hold the idea any longer.
Thus, Alan Stern proposes that we call large moons as "Satellite Planets". Yes, you heard that right: Satellite Planets!
And here's what I have to say to this idea: I like it!
A "planet" that is orbiting another planet may seem counter-intuitive at first but somehow it simplifies things once it sinks in. A "satellite" after all, is defined as a celestial body that revolves around a larger celestial body.
Now because we have this debate about what a planet is, we must forget for a moment the whole confusion about Pluto, and look at these round moons as Worlds in their own right, then perhaps one might see them as planets as well.
When the time is right, try looking at the moon in the blue morning sky. That gray crescent looks like a planet, right? Umm...well maybe its just me. Perhaps because I love planets. But now because Alan Stern is a big defender of Pluto, this idea will definitely elicit violent reactions from plutagonists. On the other hand, if he didn't love Pluto that much, he might not have been bold enough to put forward this idea. So let's see what comes of it.
In the meantime, I wouldn't mind introducing the term "Planellites" for twitter brevity.
Gasp! What have I done?! That means that we will have "exoplanellites" as another word for exomoons!
Should Large Moons be called...
Super-Earth may be a Super-Io
Grouping the Planets
Image taken from this page