Exposing PseudoAstronomy

September 30, 2011

Podcast Episode 6: Astrology Basics and a (Non-?)Changing Sky

Here’s a short post for a long podcast episode on astrology. I’ve discussed astrology several times in this blog before, though I’ve never really gone through to talk about the basics of astrology and some of its inconsistencies.

This episode is (I hope) a natural progression from the basics to talking about observational problems with precession and some inherent contradictions with that and different astrological ages, then getting into the whole “there is no mechanism!” that most astronomers use to “debunk” astrology. I wrap it up with the idea of predictions – that astrologers haven’t ever predicted the existence of astronomical objects, and a little about the anatomy of an astrological horoscope and two statistical studies into its predictive power.

I don’t ever explicitly talk about how the entire astrological system is a logical fallacy (correlation does not imply causation, or cum hoc ergo propter hoc for you Latin folks), but with the tone of the episode I didn’t really think it fit in very well. Maybe if someone sends in feedback I’ll address it during feedback of the next episode (hint: next one is based on … or in … Earth).

This episode is my longest so far coming in at about 32.5 minutes. I know in my first episode I said I’d be doing 10-20 minute episodes and my last few have gotten progressively longer. I’m not entirely sure where this is headed (gimme a break, I’m only on episode 6! (no, not 6-factorial for you math people)), so we’ll see if I’ll adjust my aims over the next few episodes.

I should also note that the episode addresses WESTERN astrology only (though a lot of the information will apply to all types). With that said, go listen!



  1. puzzler: planetary retrograde motion. Too tired to explain. Here’s a cheat: http://www.scienceu.com/observatory/articles/retro/retro.html

    Keep up the nobel efforts.

    Comment by Nigel St. Whitehall — September 30, 2011 @ 9:34 pm | Reply

    • As is my policy, I won’t confirm nor deny whether this answer is correct. But, if it is, then you probably already know it is. Stay tuned for the episode for October 16!

      Comment by Stuart Robbins — September 30, 2011 @ 9:42 pm | Reply

    • Drat you for betting me here. 😉

      Comment by Donovan Willett — October 1, 2011 @ 7:44 am | Reply

  2. I don’t use iTunes. However, note that there is many correct logic to describe about astrology being bad; some people use incorrect logic. I will explain it on here.

    The signs of the zodiac are not related to the constellations they are named after (anyways some are slightly different than the actual names of the constellations they are named after, such as Scorpio/Scorpius, Capricorn/Capricornus). What it is, is for measuring ecliptic longitude instead of splitting a circle into 360 degrees you split into 12 signs. (Astronomers often measure right ascension in hours/minutes; this is yet another way of angular measurement.) The 0 degrees is the vernal equinox (in tropical zodiac). Some astrologers do take precession into account and this is called “ayanamsha” in Sanskrit.


    Comment by Anonymous — November 5, 2011 @ 7:51 pm | Reply

    • You can follow the link in the episode to the raw MP3 file, or click here to get it (right click and save-as to download). You can also go to the link for the episode and read a full transcript. I actually did not in any way argue against the first point you made – that of how to measure constellations. What I did say about precession is that if astrology were an actual predictive system based on any science, you would know instantly whether or not to take into account precession because one way would give wrong readings and the other way would give right readings. You can’t have it both ways and get the same accuracy and claim that it’s a valid predictor.

      Comment by Stuart Robbins — November 5, 2011 @ 8:23 pm | Reply

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