Scientific aspect of Sun’sUttaraayan and Dakshinaayan –
Although we have been taught since childhood that the Sun rises from the East, but if you study astronomy then according to it, there are only two days in a year when the Sun rises from exactly the East and on all the other days of the year, the Sun is slightly towards North East or South East. This occurrence of the Sun is called the Sun’s Uttaraayan or Dakshinaayan. If we look at the word Uttaraayan and Dakshinaayan, both of them are made up of two words – North and Aayan and South and Aayan where the meaning of the wordAayan is To Pass/ Move, namely the North moving and the South moving. There are only two days in a year, when the Sun is right above us during the Midday and our shadow does not appear at that time. These two days come around 21st March and 21st September.
These two days are called ZERO SHADOW DAY in the language of Science. We know that the Earth is Tilted 23.5 degrees in its latitude and continuously rotates in its axis and also keeps revolving around the Sun. Due to this continuous rotation on its axis, is the cause of the Day and the Night and due to the tilt, the duration of the Day and the Night is not equal. Due to all these reasons, the Sun’s Rays do not fall uniformly enough on the Earth, thus leading to continuous changing of seasons.
Now, in the context of Uttaraayan and Dakshinaayan of the Sun, on the 21st of December, the center of the Sun is placed on the topmost point of the South East and from that day the Sun begins to move towards the North direction, and it shines on theTropic of Capricorn. In this way the Sun continues to move in the Northern direction continuously from December 21st, and around the 21st June it reaches the topmost point of the NorthEast, after which the sun starts moving again towards the South direction. Thus, the Sun moves Uttaraayan and Dakshinaayan in a span of six months alternatively.
Start of the Shishir (winter) season-
As per the Hindu Calender, One year is divided into six seasons –Basant (spring), Greeshm (summer), Varsha (rain), Sharad (autumn), Hemant (fall/ winter) andShishir (winter). Thus begins the Shishir season after the Hemant season. On the day the Sun moves Uttaraayan, the Hemant season ends and the Shishir season begins. If we analyse on the basis of astronomy,before the Uttaraayan, when the Sun moves towards the south direction, then the temperature gradually decreases resulting in increasing cold and when the Sun completes its South direction and starts to move towards the North, the cold starts decreasing. Thus if we analyse, when the Sun on topmost point of the South East then the it’s rays do not fall directly on the Earth. Due to this, the days are small and the nights are big and it is more cold. But when the Sun is in the Uttaraayan, it’s rays begins to fall directly on the Earth, resulting in the days beginning to become bigger and the nights becoming smaller and when the Sun is on the topmost point of the North East, it results inincreasing heat and the biggest days.
In the Hindu scriptures and Ayurveda, Shishir season is of utmost importance. Digestion power is good in this season and Til (Sesame Seed) holds a lot of importance in the festivals of this time. From the point of view of Spirituality, the Sun’s Uttaraayan occurrence has been considered very auspicious. Our history tells us that most people have attained the spiritual knowledge during this time. Amongst the most famous stories, the story of Bhishma finds mention in the Mahabharata, is the most popular. The grandfatherBhishma, lying down in a Bed of Arrows (having got hurt in the battle) kept waiting for the Sun’s Uttaraayan. Because he wantedto take advantage of this transition period of the nature. Likewise, Gautam Buddha had attained the knowledge on the third full moon after the Sun’s Uttaraayan. In India, there have been many saints, sages and scholars who left their body and attained salvation during this time.