Does today’s XKCD have an error?
Shouldn’t the graphic on the right for the second line be switch with the graphic on the right for the first line?
Yes.
The line “Ultratraditionalist: only the classical planets are planets” is wrong to count five planets. It should be seven.
Please also include a large image of the strip when you post here. There’s a link to it at the bottom of the xkcd page, right below the link to the xkcd page. Right click and type L gets it copied to your clipboard, then paste it below the link here:
Then copy paste the title text. Right click on the strip, hit Q, Ctrl-C to copy to clipboard, paste here below the image and then clean up the cruft around the text:
“Under the ‘has cleared its orbital neighborhood’ and ‘fuses hydrogen into helium’ definitions, thanks to human activities Earth technically no longer qualifies as a planet but DOES count as a star.”
I’m a heretical ultratradtionalist: we insist that Uranus is visible as a very faint and very slowly moving object, but it would have been counted as a planet if anyone could have pointed it out to ancient astronomers. The question of Vesta is still unresolved however.
I’m not sure I understand what you’re saying here. The first line has 9 planets in the middle column and 9 objects are colored green in the graphic.
The second line has 8 planets in the middle column and 8 objects colored green.
Has he fixed something you saw after he initially posted? Because it sure looks correct now.
Yes, it’s been fixed.
Oh man, I should have posted a screenshot instead of a link!
Ref the hoverover …
I get the fusion part of his comment, but I don’t get the “has cleared orbit” part.
Having natural moons doesn’t invalidate “cleared orbit”. Neither does having human-made satellites. Neither does having Trojans (Wikipedia).
So what is this proposed act of humankind which invalidates the “cleared orbit” criterion?
One of my favorite little factoids is that the four Galilean moons of Jupiter are bright enough to be visible from Earth. The problem is that there are lost in the brightness of Jupiter. Munroe has seen Jupiter, and therefore has “seen” those moons. (Note that he has seen a moon of Saturn and Uranus which implies using a telescope is okay, but he’s not used one on Jupiter?)
Maybe he’s looked at Saturn through a good telescope, and has never ooked at Jupiter. 
I think I’ve seen Jupiter but not Saturn.
The four Galilean moons are clearly visible with any optics of sufficient resolution to separate them from Jupiter. Even modest field glasses suffice.
It surprised me. The concept seemed to apply more to states in the Midwest.
Hell, I grew up in Philly and can tell you that the Pine Barrens are a vast wasteland of nothingness- perfect location to educate the next generation of New Jersians ! 
And to serve as a refuge for grotesquely mutated offspring.
Also a great landing area for Martian tripods.
I took him to mean that we’ve cluttered our orbit, but you rule that out
I think it’s called “comedic licence”. 
Heck, even Galileo’s telescope sufficed. Nowadays, even a Fischer-Price toy telescope probably has better optics.
There’s a bunch of Apollo program debris in near-Earth heliocentric orbit. S-IVB upper stages and some spacecraft/LM adapter panels. It’s not known exactly what’s happened to it (some undoubtedly came back and impacted), aside from the stage from Apollo 12, which was identified in 2002 as J002E3.
Cue up Also sprach Zarathustra
That’s almost certainly what he meant. Stuff we threw out there that has not yet coalesced into being artificial Trojans. Where “yet” might be a very very long time.