The widespread celebration of the Makar Sankranti festival and its many regional variations hint at great antiquity. In this article, we will take a journey through time, weaving together history, astronomy, calendars, seasons, agriculture and common customs, to find connections and understand the antiquity of the festival, and as an outcome, we will examine three different synchronisms for Makar Sankranti.

We first discuss points of astronomical significance, to appreciate the antiquity of the festival.

1. As the Earth rotates on its 23.5 degree tilted axis from west to east, it would appear that celestial bodies that rise in the eastern horizon set in the western horizon, except for the stars closer to the celestial North (South) Pole that would appear to circle it.

2. Earth’s annual revolution around the Sun while tilted at 23.5 degrees gives the phenomenon of seasons, due to the changing amounts of sunlight in each hemisphere, in each quarter segment of the revolution.

3. The visible stars are so distant from our solar system that they appear to be fixed with respect to the Earth’s revolution. As the Earth makes progress in its revolution each day, it would appear that the familiar constellations also change in the sky. Thus the constellations that appear in the night sky in a given month will repeat in a year’s time (ignoring the slow effect of precession, discussed in point 7). The situation is analogous to looking outside a train window on a circular track – the same scenery will appear at the same point on the circular track.

4. Due to the Earth’s tilt at 23.5 degrees, from an Earth-bound observation point, it would appear that the sunrise is offset by a small amount daily, and reaches a southernmost point – the Winter Solstice, and reverses course, and reaches a northernmost point, the Summer Solstice. Ancient Indians recognized the six-month southern journey of the Sun as Dakshinayana, and the 6-month northern journey as the auspicious Uttarayana. The epic Mahabharata, recounts Bhishma who could control the time of his death, and lay on a bed of arrows, waiting for the start of Uttarayana, for more than 92 days (Nilesh Nilakanth Oak, When Did the Mahabharata War Happen?), hinting ancient observance of the Winter solstice occurrence.

5. Indian astronomical work divided the sky into twenty-seven Nakshatras that each occupies 13 and 1/3 degree segments, approximately the distance traveled by the Moon in a 24 hour period against the fixed stars. Each Nakshatra was identified by the principal stars in that segment of the sky. The Nakshatra model forms part of the earliest corpus of Indian works on astronomy, dating to the Vedic era.

6. In addition to the twenty-seven Nakshatras, ancient Indians also divided the sky into 12 equal parts of thirty degrees each, called the Rashis. While there have been some Western assertions that ancient Indians borrowed the Rashi model from Babylon, Subhash Kak shows otherwise in his book, Astronomical Code of the Rgveda, about the Vedic origin of the Rashis, evolving from the twelve Adityas. See fig.1.

7. Due to the gravitational effects of Sun and Moon (and to a lesser extent, Venus, Jupiter and Saturn), the Earth wobbles on its axis, and completes a non-uniform cycle in about 25,771 years, referred to as Precession of Equinox. Due to this wobble, the celestial North Pole (and South Pole) appears to change over time, and the Rashis appear to drift slowly over the years. More than 2500 years ago, ancient Indians had observed and measured the wobble at a degree for every 100 years. This translates to a measure of 36,000 years, a figure repeated by Hipparchus around 150 BCE. One of the best estimates of Precession was made by Bhaskara II of Ujjain in the 12th century, to 25,461 years, and not improved upon till modern times. It is very interesting that ancient Indians had noted a time when Abhijit (the star Vega) was once the pole-star, and also a time when it was no longer the pole-star. Abhijit was at the Celestial North Pole approximately 14,000 years ago. Around 7000 years ago, it would have appeared to have “fallen” in the sky, as noted by Dr. P.V.Vartak (in Scientific Dating of Ramayana and the Vedas), calling out a reference to a passage in the Mahabharata.

We now define Makar Sankranti as the date when from an Earth-bound observation point, the Sun enters the Makar Rashi, also called Capricorn.

Ancient Indians noted the Winter Solstice as the start of the auspicious Uttarayana. At some point in the past, Uttarayana coincided with Makar Sankranti, and constitutes our first point of synchrony. We can determine the time period when the two coincided by considering the effects of Precession. Prior to that, it is instructive to note how ancient Indians and Europeans recorded the passage of time.

Subhash Kak notes that even before Vedanga Jyotish, ancient Indians’ 27-Nakshatra and 12 Rashi system used a luni-solar calendar where every 5 years, an additional month called Adhika Masa was added, synchronizing the lunar and solar years. Ancient Indians also estimated the tropical year, defined as the period when the Sun enters the same seasonal point – say, a solstice point.

Aryabhata and Bhaskara II had estimated the tropical year at 365 days, 6 hours, 12 minutes, and 30 seconds, the same figure as estimated in the ancient Indian text, Surya Siddhanta. The modern figure for the tropical year is approximately 365 days, 5 hours, 48 minutes and 45 seconds.

In the Western system, Julius Caesar instituted the Julian calendar in 46 BCE, dividing the year of 365 days to 12 months, and adding a day every 4th year, thus averaging to 365 days, 6 hours – a figure less accurate than the Surya Siddhanta. Due to this approximation, this calendar accumulated errors over the years, causing a “slip” in the dates of the equinoxes and solstices. The modern Gregorian calendar introduced in 1582, introduced a correction, where if a year is integer-divisible by 4, it is considered a leap year, except for those centurial years that are integer-divisible by 100, and with further overruling exception to those centurial years that are integer-divisible by 400, which were considered as leap years. With the modern Gregorian calendar, the equinoxes and solstices occur on approximately the same date each year, and considering Precession, has an error of about 1 day every 7700 years.

Considering the first synchrony, the Winter solstice today coincides with the Dhanus Sankranti – one Rashi away from Makar. This slip has happened due to the Precession noted earlier.

Assuming a uniform Precession rate of 25,771 years for a full circle of 360 degrees, each degree is about 71.5861 years. Rounding the figures and noting that each Rashi occupies 30 degrees, we multiply 72 by 30 to get 2160 – the approximate number of years in the past, when due to Precession, Makar Sankranti would have coincided with the Winter Solstice, approximately in 143 BCE. By simulation in planetarium software, we find that anywhere from 400 BCE to the opening centuries of the Common Era, the Winter solstice date would have coincided with the Sun rising approximately in Makar Rashi. Based on synchrony of the solstice with Makar Sankranti, we propose the festival to have been celebrated since 400 BCE. See figs. 3 and 4.

Our second dating of the antiquity of the Makar Sankranti festival is by considering the synchrony of Makar Sankranti with the Til/Sesame/Gingelly crop harvest. We notice an India-wide common aspect of celebrating Makar Sankranti – the widespread use of til in traditional sweet preparation. Til is a drought-resistant rabi crop in India, planted currently around mid-November and harvested in April, before the monsoons, taking about 90 to 120 days to grow. Paleo-botanical records suggest an antiquity of at least 3000 BCE for the multi-crop cultivation of til in Rakhigarhi sites and a few centuries later for domestic rice, and trade with Mesopotamia and Egypt in til in 2000 BCE. Up to the medieval period, Indian farmers encoded agricultural wisdom with references to nakshatras to help time their planting and reaping activities. It is fascinating to investigate a period of time when Makar Sankranti coincided with the harvest of the til crop, say in southern India, and was therefore used in celebratory sweet preparation.

Contrary to popular thought, the seasons do not change with Precession. The Milankovitch cycles predict long-term climate changes due to Precession, Obliquity and Tilt cycles of the Earth, but these do not impact the periodical seasons (might make seasons more or less severe, though!). However, if we peg our measurement of time to a Nakshatra/Rashi, that observation can change over time due to Precession. Thus an observation that “rainy season starts in Ashada Masa” can change over time due to Precession.

Our clue is that traditionally, Makar Sankranti is considered as a harvest festival. In Tamil Nadu, there are two planting seasons for Til – Thai Pattam (Jan/Feb) and Adi Pattam (July/August). Considering a 4-month growing period, the Adi Pattam crop harvest would coincide with December. Thus again, the date of about 400 BCE synchronizing the Winter solstice, Til harvest, and Makar Sankranti makes sense.

The final synchrony we examine is to ask the question, when did Makar Sankranti last coincide with Jan 13th/14th? By direct simulation on planetarium software, we find this date to be around 1500s CE. This period is startlingly, the exact period of the famous Kerala astronomer, Nilakantha Somayaji (1444-1544), author of Tantrasangrama, who would have been aware of the length of the tropical year and the effect of Precession from works of Aryabhata, Bhaskara II as well as Surya Siddhanta, and might have computed the date accordingly. This date was probably left untouched since. See figure 4.

We have examined three synchronies regarding Makar Sankranti. The first, based on synchrony with the Winter Solstice gives a date of about 400 BCE. The second, based on a synchrony of til harvest in Tamil Nadu with Makar Sankranti also suggests 400 BCE. The third, based on a synchrony with the tropical calendar, gives a date of 1500s CE.

As we celebrate Makar Sankranti, we should also celebrate the strong traditions of astronomy and mathematics, indelibly tied with the shared experience of the nation, over thousands of years.