An old notebook I've recently started working with has a strange error: Prior to version 8, a figure I generated using Drop[AstronomicalData["Planet"],-1] to display all of the currently recognized planets, along with some other data, worked fine, but in version 8, Neptune is missing. Is this a bug in 8, or am I missing something?

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    $\begingroup$ Sorry if this is rude, but that should not have been difficult to debug. Did you try to examine it at all before posting? $\endgroup$
    – Mr.Wizard
    Jan 20, 2012 at 19:34
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    $\begingroup$ Yes, always. I was even kind of proud for zeroing in on AstronomicalData as the likely offender (my code is pretty wooly), and even turned on "show changes" in the AstronomicalData documentation, but didn't catch it there (it's not called out). $\endgroup$
    – orome
    Jan 20, 2012 at 19:45
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    $\begingroup$ Don't feel bad, everyone (well, almost everyone) has asked a question with an answer that is obvious after the fact. It hurts the ego a little, but it is recoverable. $\endgroup$
    – rcollyer
    Jan 20, 2012 at 20:11
  • $\begingroup$ @rcollyer: I think my ego deserves a bit of crushing on this one: after all, I managed to look right at the solution without managing to realize that $-1-1=-2$. $\endgroup$
    – orome
    Jan 21, 2012 at 4:33
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    $\begingroup$ I always thought Pluto, in a fit of pique, would eventually bump Neptune right out of the solar system. It was just a matter of timing. Alignment of the planets and so forth.. $\endgroup$ Oct 4, 2012 at 14:13

2 Answers 2


AstronomicalData was updated to remove Pluto, so you don't need to anymore.

In[27]:= AstronomicalData["Planet"]

Out[27]= {"Mercury", "Venus", "Earth", "Mars", "Jupiter", "Saturn", "Uranus", "Neptune"}

It's been demoted to a "dwarf planet", a splendid way of avoiding saying it's not a planet like Jupiter. From the documentation in Mathematica 8:

Sadly demoted Pluto

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    $\begingroup$ And then you can check out AstronomicalData["DwarfPlanet"]. $\endgroup$ Jan 20, 2012 at 20:09

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