Islamic New Year

Today is the first day of the Islamic New Year. happy amon jadid!

Why is the Islamic Calendar different from the Chinese and gregorian calendar? I got this information from islam101.com:

The new Hijri year 1426 A.H. begins February 10, 2005 . The Islamic calendar is based on the year prophet Muhammad () emigrated from Makkah to Madinah in the year 622 C.E. (Christian Era). The emigration took place after spending thirteen years preaching Islam in his hometown, Makkah, where he met extreme resistance and severe persecutions by the people of Makkah. By the command of God, the Prophet left the city with his close friend Abu Bakr Siddique (R.A.) and escaped a death threat by the disbelievers. The event marks
the beginning of the second phase of Prophet's mission. It is the phase when Madinah became the center of an Islamic state.

The Islamic calendar is lunar. Each month must begin
with the evening when the new moon is sightable by the unaided naked eye.

Muslims are obligated to sight the crescent in every country. Different countries may begin the year at different days based on their own sightings. The calendar is called Hijri calendar. The Arabic word Hijrah means migration.