Time....Space....Unknown

2012 geophysical and cosmological speculations

John Major Jenkins and others claim that an alignment will occur when the sun rises above the horizon on December 21 2012, at which point the sun will rise in the middle of the Milky Way Galaxy, thus causing an alignment between the earth, sun, and the galactic center. It is claimed that this event will cause numerous changes on Earth. However, the event is only a visual phenomenon from the Earth’s perspective, which is caused by the precession of the equinoxes or the 26,000 year wobble of the earth, and thus only changes our perspective, not the actual position of the earth in relation to the galaxy. In short, there is no gravitational force or radiation to be expected from this event because other than the tilt of the earth, nothing will be any different from what occurs in any other solstice.
There are also claims such as those of Michael Tsarion that an actual physical alignment of our entire solar system will occur with the horizontal plane of the Milky Way Galaxy on that day. The solar system is moving around the center of the galaxy every 225 million years or so, and while doing so is moving up and down in a cycle crossing the plane every 33 million years. According to the Journal Nature, however, there is evidence of the solar system crossing the galactic plane 3 million years ago. This would mean that we are moving away from the galactic plane, not toward it, and we will not be due to cross it for another 30 million years.
There are also theories that a currently unknown planet, sometimes referred to as planet x or Nibiru, which supposedly has an odd orbit that only enters the local solar system every 3600 years will return in 2012 causing many problems. The idea is traced back to Zecharia Sitchin’s translations of Sumerian texts, and specifically to his interpretation of the VA 243 cylinder seal, which he says shows that the Sumerians knew of 12 planets (sun, moon, and ten others). This idea has been challenged by his peers, most notably Michael Heiser .
Among other possible scenarios is that a shift of the Earth’s magnetic poles may occur, and that this will leave the earth vulnerable to harmful radiation from the sun. According to NASA magnetic pole reversal does not occur on a particular day or year, but over the course of thousands of years. Furthermore, the magnetic field does not vanish during this natural cycle, but becomes more complex as it makes the transition.
Some proponents of the pole shift scenario claim that this shift would be a physical movement of the poles of the earth, and not simply a magnetic shift. This event is called a true polar wander. Earth has experienced a few degree shift in the past, but nowhere near a reversal, and there is no reason to suggest this is likely or even possible. According to William Sager, a Texas A&M Oceanographer, a slight shift in the physical pole occurs at a rate between 5 and 10 degrees per million years, which means that this event could not happen on a particular day or year but only over a long period of time.
...... ( credit : Wikipedia )