Ophiuchus

[mmcirvin]

Phil Plait rants about the "astronomers just invented a new zodiac sign" thing.

Unlike Plait, I'm pretty sure I remember the last two or three times this came up; actually, I remember reading about it when I was a kid. I'm also aware that there are people who treat astrology as a traditional art form and intuition pump instead of a divination technique based on some causal connection. (But this isn't, as far as I can tell, the mindset of most people making positive claims about astrology.)

Regardless, I get the impression that most astrologers are well aware that the "houses signs" (thanks mskala) they're dealing with aren't literal constellations, but a set of names for sections of the ecliptic based vaguely on where the constellations were thousands of years ago. From that perspective the intrusion of Ophiuchus on the zodiac shouldn't particularly matter to them at all, nor are an astronomer's concerns about these things particularly relevant.

From either direction, the fundamental misunderstanding behind this story is the idea that, in the modern world, astronomy and astrology have some kind of significant connection to one another. Since they don't, it's difficult to see how astronomers could have any effect on your horoscope, unless astrologers explicitly decide to riff on something they do.

Comments

[mskala.livejournal.com]

If you want to be perfectly accurate, I'm pretty sure that where you say "houses" above, you mean "signs." The two terms have specific and distinct technical meanings in astrology.

The signs are 30-degree segments of the ecliptic. In tropical astrology (which is the most popular kind in the West) signs are measured starting from the Spring equinox; in sidereal astrology they are measured from a specific direction relative to the "fixed" stars (and some debate exists as to which specific direction should be used for this purpose). A few fringe groups use coordinate systems other than 30-degree segments, including systems that attempt to match the constellations and/or use other than 12 signs.

But the main purpose of the signs is to ease mental computation, particularly recognition of pairs of angles that are separated by multiples of 30 degrees; bear in mind that this system was invented by people who not only didn't have computers, but also didn't have decimal place-value notation. It's much easier (for someone who's willing to memorize the sign names) to recognize that "Seventeen Aries" and "Seventeen Gemini" are 1/6 of a circle apart, than to recognize that "XVII degrees past the equinox" and "LXXVII degrees past the equinox" are 1/6 of a circle apart. Giving the intervals names instead of numbers is a mnemonic aid; their relation to constellations is, as you say, not all that close.

Imagine that you open a dozen libraries in Alexandria. You might reasonably name each one after the street it's on. But if there are more streets than libraries, that doesn't mean you must immediately open more libraries; and if some streets change their names, that doesn't mean you have to chisel all the names off your library buildings too. In this context, switching from 12 equal divisions (which has many nice divisors) to 13 divisions equal or not (a prime number) is nonsense - it negates the purpose of using signs.

The houses divide not the ecliptic but the entire sky-sphere into 12 parts, according to a formula that depends on the time and location of observation, and exactly how to define the houses - a process called "domification" - is a controversial question with many answers claimed to be right by different people. The division is unequal under most systems. Usually the first house will contain objects that have just risen, the third and fourth will contain objects near their highest vertical positions during the day, and so on. There are 12 houses and 12 signs; some people claim a symbolic connection between the houses and signs; some people even use systems in which the boundaries of the houses coincide with the boundaries of the signs, extended along lines of longitude to divide up the entire sky. But there's no fixed one-to-one correspondence between the houses and signs; even people who use "whole sign" houses will normally define the first house as whichever sign is rising at the relevant time and place, the second house as the sign after that, and so on. Which house is which depends on the geographic location and the time of day, at least; that's kind of the point of houses, since they are the only thing in most astrological charts that does depend on geographic location.

As far as I know, even the wooliest of the current crop of "OMG thirteen signs!" people haven't claimed that there should also be thirteen houses to match. Anybody who knows what a "house" is, is probably beyond the level of falling for "OMG thirteen signs" in the first place.

Most of the things that can be said about this nonsense can also be said about the "OMG new planets!" and "OMG Pluto no longer a planet!" panics.

[mmcirvin.livejournal.com]

...I think when I misused "house" I was actually thinking of the "28 mansions" in traditional Chinese astronomy.

[mmcirvin.livejournal.com]

And the modern constellations themselves are just mnemonic aids for astronomers, anyway. In principle they could describe everything with RA and declination coordinates and catalog numbers.

[lots42.livejournal.com]

I don't believe in it but I'm still mad i'm not a Tauraus anymore.

My brain is odd.

[mmcirvin.livejournal.com]

My point is, to the extent that you even care about astrological signs, nothing has changed. The constellations haven't changed, and the signs haven't changed; neither the science of astronomy nor the non-science of astrology has changed. It's just a silly media wave caused by general misunderstanding of an astronomer's debunking argument.

[urbeatle.livejournal.com]

I used to study a lot of astrology back in the '70s, and I can tell that: (1) you're right, the astrologers were definitely aware of the constellations not matching up with the signs of the zodiac; (2) the whole '60s hippie "Age of Aquarius" thing *depended* on the fact that the constellations change; (3) a couple rogue astrologers were promoting Ophiuchus as another sign even back then; and, (4) that's not the only proposed change to the zodiac.

So, astronomers and astrologers, each in their own little worlds, have known certain things which journalists have only just now gotten around to misreporting.

[mmcirvin.livejournal.com]

While I'm not personally a big fan of astrology and I think that most popular applications of it fall under superstition, pseudoscience or both, I don't like to flaunt my ignorance of anything, and I also don't like it much when skeptics raise counterarguments that are themselves technically inaccurate or irrelevant.

Trying to put down astrology just by bringing up the precession of the equinoxes and the lack of correspondence between astrological signs and IAU constellations, as if astrologers never knew about these things, strikes me as not quite cricket.