Ok so... They say the world's gonna end on the 21st of December. Right? But did they say the 21st of Dec. for China - which would mean 20th of Dec. for a good part of USA - or the 21st of Dec. for USA - which would mean the 22nd for far east Asia?

is one part of the world gonna have an extra day or another part gonna have a day less?
-solve my mystery- =P