UTTARAYANAM and DAKSHINAYANAM:According to astronomy changes in earth axis and orbit around the sun is the cause of UTTARAYANAM and DAKSHINAYANAM. When the sun rises towards north-east is known as uttarayanam. When sun raises towards southeast is known as dakshinayanam. It is hidden fact that the sun will not raise exactly in the center of east. In a year, March21 and September 23 are the two days in which sun will raise exactly on east.
AYANAM means travel. Uttarayanam means sun traveling towards north-east from equator. Dakshanayanam means traveling towards south-east from equator. The Sun travels towards North-East for 6months and South-East for 6months in a year.
Ancient Indians described this phenomenon as Uttarayanam and Dakshinayanam. Uttarayanam (6months) is single day for gods and Dakshinayanam (6months) is single night for gods. Thus one year for humans is equal to 1 day for gods. Hindus consider Lord Maha Vishnu will sleep in dakshinayanam and awoke in uttrayanam. They treat uttarayanam as precious. Ancient Indians states that we need help of gods in dakshinayanam that’s why, so many festivals, fasting and holy fires were done in dakshinayanam. Legend Bheeshma has a boon to choose his death day. Then he picked the day when Sun enters in to Uttarayanam.
Hindus give spiritual importance to the day called as Sayana Ekadashi. This day Lord Maha Vishnu will go to sleep (Deep Meditation). All Hindus will start Chaturmas Deeksha from the day onwards and ends this deeksha on Prabhodini Ekadashi which occurs in the month of November where Lord Maha Vishnu Awakes.
Interesting Facts:According to ancient texts uttarayanam is time period between Makar sankranthi (Around mid of January month) - Karkataka Sankarathi(Around mid of July month) and Dakshinayanam is time period between Karkataka Sankarathi(Around mid of July month) - Makar sankranthi(Around mid of January month).
- Sun rise and sun set are caused due to earth revolving around sun in fixed orbit. The main reason is tilt in earth axis. This tilt causes change of pitch of earth when revolving around the sun. This makes sun appear to drift towards north-east and south-east in 6months variance. We can see mid night Sun(24hours Sun light) on June 21 and December 21 at Arctic and Antarctic Circles respectively.
Scientifically sun rays are very low in the months of dakshinayanam. This lowers immunity and digestive power in humans. That is the reason these traditions and rituals came in the form of fasting, meditation and divine worship towards god. These rituals will keep up immunity power in the body.