The one that re-entered the zodiac is ophiuchus. I believe it does so every once in a very, very long while. Its re-entered around 09, so it changes the zodiacs' natural order for ppl born in 09 and onward.
Though the dates have changed for the original 12, their meaning are still the same.
It does not change the zodiac of a person born before then.
We had a topic about this in my Coven, and this is what I said about it:
The original alignment of the stars has been off for hundreds of years. The fact that there's a new constellation and technically new dates isn't a recent discovery. I've heard this has actually been officially known for a few decades.
I like and pretty much believe what this person says in this article I read:
''Update: Well, strike that, you don't get to switch your sign. At least reader StarJack says so: ''The stars are markers that drift, but our main points of reference are not directly the stars. They are the equinoxes (both spring and vernal) and the solstices which altogether make the four cardinal points of the zodiac which in turn determine the signs. The stars help us locate those points which define the SIGNS of the Zodiac which remain constant in relation to the equinox point. The CONSTELLATIONS do move about and we take that into consideration when locating planets.''''
He says that the stars define the signs while the equinoxes and solstices determine the dates of the signs. Personally, this makes the most sense to me, so this is what I'm deciding to believe.
Most, if not all Astrologers probably will not change their horoscopes to fit this 'new discovery' anyway. My new sign would have been ''Ophiuchus,'' but I doubt I would be able to find any horoscopes written for it, and in any case I am quite content being a Sagittarius.