Well, mass and size are two different entities.
I doubt they're going to judge whether a rock is a planet or not on solely mass. I know I won't. Besides, Pluto has a moon.
And now, don't go doing what my college science instructor did, once he learned and informed us that Pluto was no longer a planet, and claim I saying every planet that doesn't have a moon isn't a planet.
EDIT:
It had to have been a major conspiracy if I were taught wrong because it was countless teachers across four schools and they had textbooks that confirmed everything they were teaching me. And then, they'd either have to misteach the other students in the classes or get them in on it. I highly doubt it. It's highly unlikely.Originally Posted by Harle-Quin
FURTHER EDIT:
I've done some research and apparently Mercury is bigger than Pluto. However, I found something else interesting. I wasn't the only one who was taught Mercury was smaller.
MORE EDITING:
According to this, this is why we were taught that:
At one time astronomers thought Pluto was bigger than Mercury. Now we know that Pluto is only half the diameter of Mercury.
