Science a GoGo's Home Page Forums General Discussion Not-Quite-Science Forum 2012

Hey,
I am hoping to get some feed back here regarding this subject. I have done a little research on it, but most of the discussion groups want to talk about accension, and earth changes and yada, yada, yada (not that there is anything wrong with that), however I am a little more interested in the concrete scientific facts and possibilities. Please allow me to list some key points to start:
(1) The main thing regarding 2012 is during that year the solar system is suppose to cross through the galactic plane. As this is a scientifically verifiable act, I have tried to research whether this will indeed happen. I have read articles that say it will happen and those that say it won't. The fact that the solar system (in it's journey around the Milky Way) bobs up and down like a carousel and crosses the galactic plane in it's course, is undisputed.
(2) In viewing photos of similar spiral galaxies, from the edge in, it is evident that the galactic plane contains much debris. In the couple of photos I looked at there was a darkened area where the galactic plane was. One of the photos described this darkened area as debris, I guess it tends to congregate there much like the debris that forms the rings of Saturn. Now whether this is just dust or larger object, I don't know.
(3) However, (this is my main wonderment)
(a) In these photos with the debris areas of the spiral galaxies. there was enough debris to obscure stars behind it. Is it posiible that when our solar system enters this area that we will see a reduction in the stars that are visible?
(b) There is a current theory that cosmic rays help create the weather on Earth by affecting cloud formation. When we are passing through the galactic plane, might we also see a change + or - in the amount of cosmic radiation the Earth receives. And how will that affect our weather?
There's been all this talk about how the Earth goes through periodic ice ages, but I wonder if it might not also go through really hot periods with little clouds and little rain?

There are some good answers to those questions here:

http://www.americanscientist.org/template/AssetDetail/assetid/21173/page/1

From page 2, paragraph 2:

"Relative to the average motion of the most commonly measured nearby stars, the sun moves with a speed of about 16.5 kilometers per second, or nearly 50 light-years per million years. The sun's path is inclined about 25 degrees to the plane of the galaxy and is headed toward a region in the constellation of Hercules near its border with Lyra. The sun oscillates through the plane of the galaxy with an amplitude of about 230 light-years, crossing the plane every 33 million years. However, the sun's motion relative to the local stellar neighborhood should not be confused with its movement around the center of the galaxy, since the whole solar neighborhood (including the sun) orbits the galactic center once every 250 million years."

- So, supposing that we are to be dead-centre in the galactic plane in 2012, then we've more or less been there for the past couple of million years (nothing is about to suddenly change in the year 2012), and:

From page 2, paragraph 6:

"the sun's trajectory suggests that it will probably not encounter a large, dense cloud for at least several more million years. The consequences of such an encounter for the earth's climate are unclear"

From page 5, paragraphs 1 & 2:

"We do not know whether the interstellar cloud complex flowing past the sun is a homogeneous structure. On the basis of more distant interstellar clouds, it's quite possible that the Local Interstellar Cloud contains relatively small structures (perhaps 100 to 10,000 AU across) with very high densities (more than 1,000 particles per cubic centimeter). If our solar system should pass through such a dense cloud fragment, the dimensions of the heliosphere would change dramatically.

My colleague Gary Zank at the University of Delaware and I have recently modeled the changes that might take place should the heliosphere encounter a dense interstellar cloud. If the density of the Local Interstellar Cloud increased to 10 particles per cubic centimeter, the heliosphere would contract to a radius of about 15 AU and the heliopause would become unstable (oscillating in and out of existence). The density of interstellar hydrogen at 1 AU would increase to about 2 atoms per cubic centimeter and dramatically alter the interplanetary environment of the earth. (By comparison, virtually all of the interstellar hydrogen is ionized before it gets to the earth's orbit under current conditions.) A more severe scenario - say a cloud with a density of 1,000 atoms per cubic centimeter - would alter heliosphere physics entirely and probably contract the heliosphere to within a few AU of the sun. Planets such as Saturn, Uranus, Neptune and Pluto (all of which are outside 9 AU) would be fully exposed to the flux of interstellar neutrals. Interstellar gas would overwhelm the solar wind at 1 AU. These simulations suggest that, to a certain extent, the solar wind acts to "protect" the inner planets from certain types of changes in the local galactic environment."

- According to which (correct me if I'm wrong, anyone) it is possible that an encounter with a relatively dense interstellar gas cloud may severely affect Earth's environment, in much the same way as a local supernova, by destruction of the ozone layer.