New Year is the time at which a new calendar year begins. Today Gregorian calendar which was introduced by Pope Gregory in 1582 is internationally accepted. Before that Julian calendar was used.
According to this calendar, January -1 has been taken as the first day of the year. There are 365 days in the year, since earth takes this much time to go around the sun in completing one rotation. There are two solstices in the year. One is winter solstice, when sun reaches farthest from the celestial equator. Second is summer solstice, when sun is nearest to the equator. In India winter solstice arrives around Dec 21st (Shortest day) and summer solstice on June 22nd (Longest day).
Why does the year stars on January 1? December 21 shortest day of the year would have been the best day, when days started lengthening again. Another choice was 25th December (Christ’s birth day).
January is named after Latin word JANUS, god of doors and gates, which signifies god of beginnings and transitions. Like Lord Ganesha, Janus God is worshipped before one embarks on any task or project. Since he is God of beginning January -1 is taken as New Year’s Day.
Other months are also named after the Latin names of Roman gods. February:-Februalia (God of purification), March:-Mars (God of wars), April:-Aprilis (To open-buds), May:-Maia(goddess of spring- growth of the plants) ,June:- Junies (goddess of marriage and well being of women ), July:-Julias ceaser, August:-Augusto Ceaser. Sept, Oct, Nov, and Dec. from Latin words Septum (Seven) Octo (eight) Novem (Nine) and Decem (Ten) respectively .
The New Year signifies to forget the past differences and start a new beginning of love and peace. Thoughts of ego, anger, hatred, jealousy attract negative energy, where as positive, pure and selfless thoughts attract blessings.