'Sani Peyarchi' - transition of Saturn from one moon sign to the next is happening on June 26, 2005.
Usually this transition happens every 7.5 years, i.e. every moon sign will be under the influence of Saturn for a period of 7.5 years.
Now calculating 7.5 years from June 26, 2005 we end up in December 26, 2012.
Even though it's off by 5 days, probably the actual Saturn transition might happen on December 21, 2012. I will have to confirm that. I assume the transitions don't happen exactly after 7.5 years, but few days before or after.
So many things happen to fall on this magical date on 2012.
I think this Saturn transition also has a major role to play on 2012.