In India, ordinary years are made up of 12 lunar months; these years consist of 354 or 355 days. An additional 13th month is added every three years, producing 383, 384 or 385 days for these intercalary years.The start of each month is determined by the meridian of Lanka, which the Hindus pinpoint on the equator at 90 degrees longitude. Each lunar month comprises a light half and a dark half. The Hindus introduced weeks consisting of seven days with names corresponding to our own long ago. Ravi-vaara: Sunday Soma: Monday Mangala: Tuesday Budh: Wednesday Guru: Thursday Shukra: Friday Shani: Saturday The ruling class introduced a solar year divided into 12 months named as follows: (in ancient Bengali, new Bengali, Tamil, and precise duration) 1 Mesh Vaisakha Chiththirai 30 days 925 2 Vrushabh Jyeshta Vaikaasi 31 days 403 3 Mithun Aashaadha Aani 31 days 610 4 Kark Shraavana Aadi 31 days 470 5 Simha Bhadrapada Aavani 31 days 037 6 Kanya Ashwin Purattaasi 30 days 457 7 Tula Kartika Aippasi 29 days 902 8 Vrushchik Agrahayana Kaarththigai 29 days 507 9 Dhanu Pausha Maargazhi 29 days 347 10 Makar Maagha Thai 29 days 455 11 Kumbha Phalguna Maasi 29 days 807 12 Meen Chaitra Panguni 30 days 339 The length of each month is determined by means of astronomical calculation. A sidereal year is estimated at 365 days, 6 hours, 12 minutes, 36 seconds. The Hindus use the duodecimal numbering system. The Calendar day, which begins at sunrise, is divided into 60 parts, each of which is divided into a further 60 parts, and these again into 60. The astronomical day is divided eight times in succession into 60 parts. A plethora of eras and periods of all sorts sprang up in India. Its mathematicians gave full rein to their imaginations. The following epochs relate to the solar year: Kali Yuga which starts on 20 January 3102 BC. Lokakala which begins on 24 January 3078 BC. Buddhist which begins on 28 February 544 BC. Samvat-Vikramaditya which begins on 6 March 59 BC. Kalachuri which begins on 2 March 249 AD. Valablki-Samvat which begins on the 23 September 301 AD. Fasli which begins on 23 March 593 AD. Burmese which begins on 1 March 637 AD. Siwa-Simha-Samvat which begins on 28 February 1112 AD. An additional feature of the Hindu calendar is the great ages of the world, each composed of three parts: dawn, the age itself and twilight. These are: The golden age of Krita Yuga lasting 1,728,000 years The silver age of Tret Yuga lasting 1,296,000 years The bronze age of Dvapara Yuga lasting 864,000 years The iron age of Kali Yuga lasting 432,000 years Together, these four periods constitute a Maha Yuga of 4,320 years. All 71 Maha Yugas, in addition to one twilight lasting 1,728,000 years, make up a Manvantara or Patriarchy which, combined with one in the autumn of 1,728,000 years, forms an aeon or kalpa of 4,320,000,000 years. Now, this kalpa corresponds to just one day in the life of Brahma; one night is the same length as this life which lasts 100 years. Brahma's entire lifespan therefore is 31,104 x 1,010. Which is just one instant of Sira! Brahma's life is currently nearing its end; we are living in the second half of Brahma's life, in its first kalpa, its seventh Marantara, its twenty-eighth Maha Yuga and its iron age which began in 3102 BC! Evidently, the universe was no longer a mystery to the sages!