According to *something,* (I do not remember where I read that phrase) we are on the "dark side" for 26,000 years, and then we shift over to the "sunny side." I don't remember where I read it, and that's why I put it in quotes. Those are someone else's words, not mine. But I am nearly positive it has anything to do with increased or decreased brightness. It may have to do with positive and negative magnetism. It me just be an arbitrary distinction, I do not know. But what IS important, is that every 26,000 years, we DO cross the strongest point of magnetism, as we align with the center of the galaxy.
To be honest I don't know about what you are talking about.
I am not too familiar with englisgh terminology but I will try to answer.
There is a 26 000 cycle which is about changes of the Earth axis. But that doesn't have anything to do with the rest of the the galaxy.
Maybe I am wrong but if we have such a dangerious cycle that includes magnetism don't you think we should see same bad efects. Since we have only 3 years out of 26 000 left ?
But we have about 250 000 000 years cycle, which is how long it takes for solar system to make a cyrcle around the supermassive black hole in the center of the galaxy. But as we cyrcle around we also go up end down so we pass through a galactic plane from time to time.(i don't know how often)
But Earth exists for a 4.6 billion years so i don't see what really new can happen. We are constantly under efect of that super massive black hole so I don't see the problem. Especially since we have been through the "danger zones". Ok, now we have the technology but the cycles of our sun have much larger efect on Earth then the black hole can have.
Since it is about 300000000000000000 kilometers away from Earth and Sun.
If I got the math right.
While sun is only about 150 000 000 kilometers away.
So the ratio is about 1: 2000000000 in the distance sun/black hole.
Plus the entire galaxy is constantly efected by the massive black hole.
Another thing is that ancient civilizations were not aware of this.
So I dont see how they could have known that the porblem will occure exactly in 2012 if it were accure in which i doubt.
Plus they must have known that we will develop technology that can brake down in a event about which you are talking about. Since for ancient civilizations there would be no real harm since there was no complex technology back then. But this doesn't happen so often, so the last tome was probably long before mankind even existed. Plus fossil record doesn't show any real correlation with this. In the case it is a real problem.