The world as we know it ending in 2012?.. What merit do the Mayans hold that we should believe this?

I know the Mayans were a brilliant people as the Ancient Egyptians were, but what have they predicted correctly that gives them any credibility in predicting the future? Seemingly many people believe their prediction that violent cataclysmic events will occur on earth in late 2012 resulting in mive loss of life. what prophesied events have been fulfilled in the past that gives the Mayans merit? Also, what do today's SCIENTISTS think will happen as the the sun aligns with the center of our milky way galaxy around 2012 (if that's even correct)? Is there any immediate concern for this phenomenon (the sun's alignment) Outside the astrology-believing community?