Hello again Lindsay;
I'm going to beat 
Alene Y to the punch here, and say that you shouldn't worry about pestering us. The entire reason for the site's existence is to reassure people that 2012 will be an entirely normal year.
As far as the galactic plane is concerned, there are a couple of different scenarios or claims that are made, and frequently these different claims get confused and mixed up with each other, and with the period of the earth's precession.
As Dr. Larsen explains it, if you think of the galaxy as a fried egg (with the yolk as the bulge, and the white as the disk) then the 'galactic plane' is the flat plane that would pass through the whole shebang, intersecting the edge of the disk, all the way around. Here's the important bit: The galactic plane is a human approximation. It is supposed to roughly correspond to the center of mass of the disk, but of course there are all kinds of exceptions, because nature is not as neat and tidy as we tend to think. If you lived in the Southern Hemisphere you would be familiar with the Magellanic clouds, which are actually small companion galaxies to the Milky Way. These small galaxies have been found near other large galaxies as well, and we can see that they warp the 'galactic plane' so that it is no longer flat. In some cases it looks like a 'galactic saddle' or perhaps 'galactic tostada'. So it is reasonable to infer that the galactic plane of our galaxy may be similarly warped.
In fact, the margin of error in determining the position of the galactic plane is several light years.
So there's a problem with the whole idea of this region as a fixed point in space. In addition, there's the problem (for the people who say we are going to be passing through the plane) that when we measure the motion of the solar system through the galaxy (and this is done by surveying the speeds of stars both moving toward us and away from us) we find that the solar system is moving toward the galactic north. We also find that we appear to be to the galactic North of the galactic plane. In other words, we are moving away from the galactic plane, not toward it.
It turns out that stars (and solar systems) not only orbit the center of the galaxy (every couple hundred million years) but also kind of wobble up and down, like a cork bobbing along in a stream. It takes about 33 million years for us to bob up, and then back to the center, then another 33 million for us to bob down, and then back to the center.
As best we can tell, we would have passed through the galactic plane a few million years ago, and we probably won't be back for another 30 million years or so.
And finally, the biggest problem for this idea is the relevance. So, we pass through an imaginary plane in space. So what? The proponents can't point to any reasonable mechanism for why this would present a problem.
A separate claim that is made is that the earth will "align" with the galactic plane. Speaking from a sense of 3-dimensional geometry, this doesn't make sense. The Earth is part of the solar system, which is not on the galactic plane. So you have a point, and a plane that doesn't touch the point. What kind of 'alignment' can you seriously talk about? It's like holding a pencil above a table, and claiming that the point of the pencil is 'aligned' with the table. Sometimes the claim is made that the line between the earth and sun will intersect the galactic plane. This is true. But it does that for most, if not all, of the year.
Wow, I didn't mean to write such a long response. I think I'll leave planetary alignments to someone else.
Lindsay (guest) 02 Sep 2010 19:35
