How are the muslim and chinese calendars different

If Christ saved everyone in the whole world, why haven't the whole world adopted to his calendar?

I think the Chinese have 8,400 years on their calendar.

And Jewish have 7,210 years on their calendar.

How can they have more years, if the world is only 6,000 years old?

Bis your correct answer

Upheld the 1st amendment according to the u.s constitution. freedom of speech being limited in this case yes national emergencies