In 1905 Einstein showed in his theory of relativity that time is affected by motion so that the faster one goes the slower time does.
The first day of the year in the Gregorian calendar is 1 January.
The first month in the Jewish calendar is Nisan (March/April in the Gregorian calendar), although years are numbered from Tishri, the 7th month.
The first month in the Hindu calendar is Chait’r (March/April in the Gregorian calendar).
The Chinese New Year occurs at the second new moon after the beginning of the Northern Hemisphere winter, thus between 20 January and 20 February.
The Hindu calendar dates from about 1000BC.
The Chinese calendar begin in 2637BC.
The Jewish calendar began at the moment of creation, 3760 years and 3 months before the beginning of the Christian era. It ends in the year 2240.
The End of the Muslim Calendar is the year 2076
According to the Mayan calendar we are now in the Age of the Fifth Sun which began in 3113 BC and will end on 21 December 2012 AD, the year all its reference to time ends. It also is the end of the Hindu Kali Yuga cycle and the year the Greeks refer to as Suntelia Aion, the End of the Age.