Astronomical Significance of Makara Sankranti

#CandleInTheDark

Happy Pongal, Makara Sankranti, Bihu, Lohri and Uttarayan!

An occasion to worship our life giving star, The Sun.

I asked around many people about why we are celebrating this festival this time of the year. The response is pretty consistent. It is a harvest festival! I was not satisfied with that answer. Then I did some search on the net, then I realised that the term "Sankranti" (Sanskrit: संक्रान्ति saṁkrānti) means transmigration of the Sun from one Rāshi (constellation of the zodiac in Indian astronomy) to the next. See the picture below. As Earth orbits the Sun, the Sun appears to be moving from one Zodiacal Constellation (there are 12 of them as depicted in this picture) to another (the transmigration mentioned above). So actually there are 12 Sankrantis in an year.

OK, so what is so special about Makar Sankranti, when Sun transmigrates into Makaram (a.k.a. Makar, Makaram, etc) or Capricornus constellation? And this day is also celebrated as Uttarayan (a.k.a. Uttarayanam). But hang on! Uttarayan means beginning of the Northbound "movement" of the Sun (note the "movement" is in quotes because it only appears to move, but we are the ones actually moving). But the Sun started the Northbound "movement" on December 21st (December Solstice). So why is this day called as Uttarayan? This is where Astronomy comes into play.

Our forefathers had great knowledge on Astronomy. They knew that on the day of the December Solstice, Sunrays reaches the Southernmost latitudes (due to the axial tile of our beautiful planet). From that moment, as our beloved planet continue its 4.5 billion old motion around our life giving Sun, the Sunrays start receding from the southern latitudes as the Sun appears to move from the Southern latitudes to the North. Uttarayn begins! Yes, I know what you must be wondering about! If Uttarayan was actually on 21 December, then why are we celebrating now? Astronomy gets more interesting from here. Read on...

If Uttarayan was actually on 21 December, then why are we celebrating now?

Precession of the Equinoxes

When all these were observed by our forefathers, they realised that as Earth spins at the rate of 1000 miles per hour, it wobbles like a top (see the first picture below) due to the torque exerted by other bodies like the Moon and the Sun. This wobble is so slow, it completes one full circle of the wobble across 25,772 years. That means, in which date the Sun appears to enter Makar (Capricornus constellation) keeps shifting to the right. So our festivals that are based on Sun's movement (like Uttarayan, Pongal, Makar Sankranti, etc.) will continue to come 1 day late every 71 years. So thousands of years ago, All those festivals that are celebrated on 14/15 January actually was celebrated on 21 December (the day of the December Solstice). It is amazing to note that our traditional calendars already considers these and make necessary adjustments to the date to account for this shift.

OK, it has been coming one day late every 71 years since 21 December. Does it mean it will continue to shift right? That's correct!

Is the reason Makar Sankranti is celebrated losing its significance?

Taking the 71 year shift into consideration approximately 1000 years ago we started celebrating this to usher in warmer months (i.e. the start of the actual Uttarayan on winter solstice, 21 December). But another 1000 years from now, this will move into summer months and then further into the future it will continue to shift eventually stopping at June Solstice (21 June). That will be the beginning of Monsoon period in India. That further means, we will no longer be ushering in warmer months, but wetter months! That is a long way from now and chances are we would have stopped celebrating our festivals assuming humanity is still around!

Please do not ignore the December Solstice

Though our celebrations are based on when Sun appears to enter the Makar Rasi (Capricornus constellation), please do not ignore the December Solstice. Let us celebrate that as well in equal enthusiasm to worship and respect our life giving star, the Sun, and the wonder of a planet called the Earth.