December 21 is not the critical event in 2012, June 4±2 is much more stressful.
On Dec 21, the Sun is conjunct a line which was defined by the Astronomical Union in 1958 to be the Galactic Equator.
This line was in the approximate middle of the Milky Galaxy as it was then known. Now more sensitive detectors using infrared and x-rays have found the Galactic Center, thought to be a be a super dense entity called a black hole, at a point about 5° off the previously defined Galactic Equator. The Sun does not conjunct it and never will in many thousands of years. The December 21 event is similar to every winter solstice. The Sun, as seen from Earth, appears close to, but not exactly aligned with the central black hole. This has been the case every year for over two decades, and will continue to be close for more than two decades after Dec. 21. Its conjunction with the Galactic Center is a more or less arbitrary event. It has no physical reality.
On June 4 though, there is a real, solid, tangible event. The planet Venus transits, or goes exactly across the disk of the Sun, a rather rare event. There is a full Moon, a partial eclipse, and the Moon is closest to Earth of the month!!! These factors may greatly increase any stresses on Earth’s crust, perhaps increasing earthquake and volcanic activity. If this happens in 2010, it will probably happen again with increased strength.
Expanded Screenshot image from the Dynamic Solar System© software. June 4, 2012.
For more information go to buryl.com under 2012 - there are graphic worth seeing on my website that would not post here.