Refutation of Nilesh Oak’s dating of ancient texts

Surya Siddhanta was NOT written over 14,000 years ago

Refutation of the article “Ancient updates to Sūrya-siddhānta” by Nilesh N. Oak and Rupa Bhaty

In an article in IndiaFacts and two presentations [1–3], Nilesh N. Oak and Rupa Bhaty have claimed that astronomical text Sūrya Siddhānta contains information that can be dated to 12,000 BCE. Oak and Bhaty have cited three astronomical observations from Sūrya Siddhānta that can be simultaneously satisfied only in 12,000 BCE [1]:

The two necessary conditions (two pole stars and points of apoapsis/periapsis during Hemanta/Grishma, respectively) and the optional yet desired third condition of the Earth’s obliquity (equal to 24°) are all satisfied by the year 12000 BCE!

Oak and Bhaty accept that Sūrya Siddhānta was last updated in 580 CE, which is the accepted date of Sūrya Siddhānta. However, Oak and Bhaty propose that even during the last update, pieces of information that had clearly been long outdated were still left as it is [1]:

The analysis of two updates (580 CE & 12000 BCE) indicated that every instance of update did not result in exhaustive updating of the entire text.

If this is true then clearly all of the editors of Sūrya Siddhānta over this long period from 12,000 BCE to 580 CE were a bunch of idiots and not astronomers, who didn’t know how to update astronomical information that has become outdated. In this article I will show that the conclusions drawn by Oak and Bhaty are wrong and all three observations were BELIEVED to be true by the editors of Sūrya Siddhānta during its last update in ~580 CE. I will begin by discussing why Sūrya Siddhānta cannot be older than 2,000 BCE.

1. Sūrya Siddhānta cannot be older than Vedāṅga Jyotiṣa

The Vedāṅga Jyotiśa is the first astronomical text of ancient India. It comes in two recensions: Ṛk and Yajus. It is mentioned in the verses 6–8 of the Yajus Vedāṅga Jyotiṣa that the winter solstice was at the beginning of the Śraviṣṭhā (Dhaniṣṭhā) nakṣatra and the summer solstice was at the midpoint of the Āśleṣā nakṣatra. Based on this observation, the Vedāṅga Jyotiśa is dated between 1150 BCE to 1400 BCE [4]. Here is the relevant verse from Vedāṅga Jyotiṣa:

prapadyete śraviṣṭhādau sūryācandramasāvudak|

sārpārdhe dakṣiṇārkastu māghaśrāvaṇayoḥ sadā||

(Ṛk Vedāṅga Jyotiṣa 6/ Yajus Vedāṅga Jyotiṣa 7)

Its translation is English is as follows [5]:

When situated at the beginning of the Śraviṣṭhā segment, the Sun and the Moon begin to move north. When they reach the midpoint of the Āśleṣā segment, they begin moving south. In the case of the Sun, this happens always in the month of Māgha and Śrāvaṇa, respectively.

Based on this verse, the positions of solstices and equinoxes are as shown in Figure 1. The dating of this observation depends on the position of nakṣatra boundaries in the sky. Based on currently accepted positions, the date comes out to be 1150 BCE to 1400 BCE as mentioned earlier. From my research work, the original boundaries of nakṣatras are different from currently accepted positions and I have dated the observation to ~1850 BCE [6–8].

Figure 1: Position of the sun during solstices and equinoxes as specified in Vedānga Jyotisha

Thus the time of composition of the Vedāṅga Jyotiṣa is 2nd millennium BCE. Now the Vedāṅga Jyotiṣa is decidedly earlier than Sūrya Siddhānta. Vedāṅga Jyotiṣa has 5-year yugas compared to the 4.32 million years Mahāyuga system of Sūrya Siddhānta. Vedāṅga Jyotiṣa deals mainly with the motion of sun and moon, while the Sūrya Siddhānta deals with motion of planets as well. Sūrya Siddhānta is simply too advanced compared to Vedāṅga Jyotiṣa and there can be no doubt that Sūrya Siddhānta was composed much later than Vedāṅga Jyotiṣa. Thus the upper limit on the date of the composition of Sūrya Siddhānta is the date of the composition of Vedāṅga Jyotiṣa and Sūrya Siddhānta cannot be dated to any time period earlier than the 2nd millennium BCE. With this background I will show that all three observations cited by Oak and Bhaty are consistent with the state of astronomical knowledge in ~580 CE and do not require a date of 12,000 BCE.

2. Two pole stars

First astronomical observation cited by Oak and Bhaty is the existence of two pole stars at the same time mentioned in Sūrya Siddhānta 12:43–44 [1].

Here is the text of Sūrya Siddhānta 12:43–44:

merorubhayato madhye dhruvatāre nabhahsthite |

nirakṣadeśasaṃsthānāmubhaye kṣitijāśriye ||43||

ato nākṣīcchrayastāsu dhruvayo: kṣitijāsthayoḥ |

navatirlambakāṃśāstu merāvakṣāṃśakāstathā ||44||

Oak and Bhaty translate it as [1]:

There are two pole stars, one each, near Northern celestial point (NCP) and near Southern celestial point (SCP). From equatorial locations, these stars are seen along the horizon. The pole stars are seen along the horizon, from these places, and thus the place latitude is close to zero, while the declination of NCP & SCP is 90 degrees.

The English translation by Burgess is as follows [9]:

In both directions from Meru are two pole-stars (dhruva-tārā), fixed in the midst of the sky: to those who are situated in places of no latitude (niraksha), both these have their place in the horizon.

Hence there is in those cities no elevation of the pole, the two pole-stars being situated in their horizon; but their degrees of co-latitude (lambaka) are ninety: at Meru the degrees of latitude (aksha) are of the same number.

It should be noted that in the quoted verses in Sūrya Siddhānta, there is no mention of North celestial pole (NCP) and South celestial pole (SCP). Oak and Bhaty have taken the liberty of adding “near Northern celestial point (NCP) and near Southern celestial point (SCP)” in the translation, which is not there in the verses. This is of critical importance as the authors of Sūrya Siddhānta mean NCP and SCP by the word dhruva-tāre in these verses [10]. If this is so, then pole stars as well as NCP-SCP will not be mentioned together in these verses. This can be verified by reading the verses in Sanskrit.

Oak and Bhaty claim that there was no visible South Pole Star in last two thousand years. Going back, Oak and Bhaty come with different time periods when two pole stars existed such as 2,900 BCE and 12,000 BCE. Oak and Bhaty then choose 12,000 BCE based on two additional astronomical observations. The central claim made by Oak and Bhaty in support of 12,000 BCE date is this [1]:

In the year 12000 BCE, Vega (Brahmarashi or Abhijit) was the North pole star and Canopus (Agastya) was the South pole star.

To refute this claim, it is important to understand the difference between celestial pole and pole star, which requires the understanding of equatorial coordinate system. There are many coordinate systems used to specify the position of a star. Equatorial coordinate system measures the coordinates from and along the celestial equator, which is the projection of the earth’s equator on the celestial sphere. The poles of the celestial equator are called North Celestial Pole (NCP) and South Celestial Pole (SCP), which are the projections of the North Pole and South Pole on the celestial sphere respectively. Equatorial coordinates are specified by providing declination and right ascension. Figure 2 illustrates the equatorial coordinate system. In this picture P is the North Celestial Pole (NCP), ♈ is the first point of Aries (intersection of the ecliptic and celestial equator), S is the location of a star, and P′ is the South Celestial Pole (SCP). Declination of the star is given by SA and the right ascension of the star is given by ♈A. In equatorial coordinate system, the declination is determined by measuring the angular distance from the celestial equator to the star along the great circle passing through the star and the North Celestial Pole. Right ascension is determined by measuring the angular distance along the celestial equator from the first point of Aries to the intersection of the celestial equator and the great circle passing through the star and the North Celestial Pole.

Figure 2: Illustration of equatorial coordinate system

North Celestial Pole (NCP) and South Celestial Pole (SCP) are mathematical points around which the stars appear to rotate. A star is called a North Pole Star or simply North Star if it is close to the NCP and South Pole Star or simply South Star if it is close to SCP. The question is how close? Obviously, it should be so close that all stars should appear to be rotating around the pole star. Distance in space for current purpose of the article is measured in angular distance. The angular distance of full moon is only half degree. So if a star is a few degrees away from NCP or SCP, it will be seen to be rotating around the NCP or SCP by careful observation. The cut-off point is 5° away from NCP or SCP to be called a pole star [11]. So the declination of a star must be between 85° and 90° to be called a North Pole Star and between -85° and -90° to be called a South Pole Star.

The star configurations in 12,000 BCE around NCP and SCP are shown in Figures 3 and 4 using Stellarium software. It can be seen that Vega had a declination of 86° 14′ in 12,000 BCE, so it was the North Pole Star then. However, the declination of Agastya (Canopus) was -78° 14′, so it was NOT the South Pole Star by any stretch of imagination. It is nearly 12° or 24 full moon diameters away from SCP and calling it South Pole Star is simply absurd. Anybody watching it would have known that it was not fixed but rotating through the night. Table 1 shows the declination of Agastya (Canopus) from 0 to -20,000 BCE with more data points around 12,000 BCE. It can be seen that Agastya (Canopus) got closest to SCP in 12,000 BCE but it was never a pole star between 0 to 20,000 BCE. However, the proponents of fantastic high chronology are fixated to Agastya (Canopus) being South Pole Star in 12,000 BCE without knowing that declination needs to be between -85° and -90° to be called a South Pole Star.

Figure 3: The coordinates of Vega (Abhijit) in 12,000 BCE
Figure 4: The coordinates of Canopus (Agastya) in ~12,000 BCE
Table 1: Declination of Agastya (Canopus) from 0 to -20,000 BCE (Source: Stellarium)
Table 1: Declination of Agastya (Canopus) from 0 to -20,000 BCE (continued)

One of the authors, Bhaty, claims that Canopus was South Pole Star according to Wikipedia in the article “Astronomical Association of Natarāja’s Dance with Apasmara and Agastya” published in IndiaFacts [12]. Bhaty writes [12]:

In nutshell, after evaluating the empirical evidence and by testing them, it was found that the latitude of Chidambaram [Chitt +ambaram; ambaram in Sanskrit means sky, horizon, compass] was the threshold from where Agastya became invisible while navigating due north away from this latitude when Canopus was at its highest declination, very near to the south celestial pole being a pole star [https://en.wikipedia.org/wiki/Pole_star]. This astronomical event happened during 11000BCE-13000 BCE.

However, the Wikipedia page nowhere says that Canopus was a pole star at any time in past. Instead it says this [11]:

Around 14,000 AD Canopus will have a declination of –82°, meaning it will rise and set daily for latitudes between 8°S and 8°N, and will not rise to viewers north of this latter 8th parallel north.

This is a time in future, not past, and even then Canopus will not be South Pole Star. Wikipedia does not say that Canopus will be South Pole star in 14,000 AD. In a table on the same Wikipedia webpage, stars more than 5° away from NCP are called near-north star and only the stars less than 5° away from NCP are called North Star that is North Pole Star. Clearly Bhaty has not even bothered to read the Wikipedia page properly which she has cited.

Furthermore, Oak and Bhaty accept that Thuban was the North Pole Star in 2,900 BCE [1]:

In the year 2900 BCE, Thuban was the North pole star and Alpha Hydri or Alpha Eridani was the South pole star.

Figure 5 shows the coordinates of Thuban in ~2,900 BCE. It was a Pole Star as its declination was 89° 20′. Please note that the magnitude of Thuban is 3.65 as shown in Figure 5.

Figure 5: The coordinates of Thuban in ~2,900 BCE

Now compare this to the star configuration around North Celestial Pole in ~320 BCE. At that time Greek navigator Pytheas said that there was no Pole Star. Here is what Wikipedia says about Pytheas [11]:

During the 1st millennium BC, Beta Ursae Minoris (“Kochab”) was the bright star closest to the celestial pole, but it was never close enough to be taken as marking the pole, and the Greek navigator Pytheas in ca. 320 BC described the celestial pole as devoid of stars.

Figure 6 shows the coordinates of Kochab in ~320 BCE. Please note that the magnitude of Kochab is 2.05 as shown in Figure 6. Table 2 shows the declination of Kochab during 1st millennium BCE. The declination of Kochab was 82° 34′ in ~320 BCE, far closer to celestial pole than -78° 14′ for Agastya (Canopus) in 12,000 BCE. Kochab has magnitude of 2.05 and thus Kochab is much brighter than Thuban with magnitude of 3.65. Still Pytheas in ~320 BCE did not consider Kochab a Pole Star. Even in ~320 BCE Greek navigator Pytheas knew that a star more than 7° away from North Celestial Pole could not be called a Pole star, but Oak and Bhaty have made Agastya (Canopus) a South Pole star in 12,000 BCE that was 12° away from South Celestial Pole.

Figure 6: The coordinates of Kochab in ~320 BCE
Table 2: Declination of Kochab from years -1000 to 0 (Source: Stellarium)

Oak and Bhaty claim further support for Abhijit (Vega) being North Pole Star and Agastya (Canopus) being South Pole Star from Sūrya Siddhānta 13:8–9 [1].

There is a direct evidence of placing Abhijit and Agastya in north of Northern and south of Southern hemisphere respectively as NCP and SCP from the armillary section in Chapter 13:8, 9 of Sūrya-siddhānta. This comes as one more evidence of Abhijit and Agastya to be in extreme north and south.

Here is the text of Sūrya Siddhānta 13:8–9:

yāmyagolāśritāḥ kuryāt kakṣyādhāradvayopari |

yāmyodagbhāgasaṃsthānāṃ bhānāmabhijitastathā ||

saptarṣīṇāmagastyasya brahmādīnāṃ prakalpayet |

madhye vaishuvatī kakṣyā sarvāsāmeva saṃsthitā ||

The English translation by Burgess is as follows: [13]

Those likewise of the asterisms (bha) situated in the southern and northern hemispheres, of Abhijit, of the Seven Sages (saptarshayas), of Agastya, of Brahma etc., are to be fixed. Just in the midst of all, the equinoctial (vaishuvatī) hoop is fixed.

Hindi translation by Śrīvāstava is also similar [14]:

It should be noted that in the quoted verses in Sūrya Siddhānta, there is no mention of NCP and SCP. Oak and Bhaty have taken the liberty of claiming that Abhijit and Agastya are located at NCP and SCP respectively according to Sūrya Siddhānta 13:8–9. Verses only say that Abhijit (Vega) and Agastya (Canopus) are to be fixed at their proper positions in northern and southern hemispheres. This can be verified by reading the verses in Sanskrit. This is clear case of manufacturing of evidence.

Thus the claims that Canopus (Agastya) was South Pole Star in 12,000 BCE and Canopus (Agastya) is mentioned as South Pole Star in Sūrya Siddhānta are totally false. So enthralled are the proponents of fantastic high chronology about Agastya (Canopus) being the South Pole Star in 12,000 BCE that they don’t ask themselves the very basic question: can South Pole Star be observed from anywhere in India?

The extreme point in south in mainland India is Kanyakumari at a latitude of 8.09° North. This means that the horizon from Kanyakumari is 90° away at ~ -82°. So, the SCP is ~8° below horizon from the most southern point of India. Thus a South Pole Star has never been visible from India and never will be. Indian astronomers cannot be talking about a South Pole Star which they had no means to observe. Therefore, it makes perfect sense that though Sūrya Siddhānta uses the word “dhruvatāre” meaning pole stars, it actually means NCP and SCP as explained by Śrīvāstava, writer of a scientific commentary on Sūrya Siddhānta [10]:

It is a style of our ancestors to give physical attributes to scientific concepts and people not understanding this style come up with all kind of fantastic high chronology.

Furthermore, Oak and Bhaty write in the same article [1]:

Shri Shrivastava, in his vigyān bhāshya of Sūrya-siddhānta writes that if earth is taken as geocentric object then these retrograde motions will remain unexplained.

This means that Oak and Bhaty are aware of the explanation proposed by Śrīvāstava in his scientific commentary on Sūrya Siddhānta. However, they chose to not disclose this critical information to readers. Oak and Bhaty should have quoted this important information and then refuted it. Oak and Bhaty have tried to make a point based on reader’s ignorance instead of being transparent and putting all the cards on the table. It is fundamental principle of scientific research that conflicting information must be disclosed.

If one has read Indian astronomy texts carefully, it would have been obvious that Indian astronomers were describing NCP and SCP which are theoretical points and not North Pole Star and South Pole star, which are actual stars. Due to the lack of this understanding of the style of ancient Indians to preserve their knowledge base, Oak and Bhaty have made preposterous claim that Sūrya Siddhānta was written over 14,000 years ago. The claim is without merit as Canopus was clearly NOT a South Pole Star in 12,000 BCE. Having refuted the dating of the first astronomical observation by Oak and Bhaty, let me refute the second astronomical observation.

3. Earth’s obliquity

According to Oak and Bhaty [1], second astronomical observation supporting a date of 12,000 BCE is the value of 24° for earth’s obliquity given in Sūrya Siddhānta 12:68.

The text of Sūrya Siddhānta 12:68 is as follows:

bhūmaṇḍalāt pañcadaśe bhāge daive tathā’’sure |

upariṣṭād vrajatyarkaḥ saumya yāmyāyanāntagaḥ ||

Its English translation by Burgess is as follows [15]:

The sun, during his northern and southern progresses (ayana) revolves directly over a fifteenth part of the earth’s circumference, on the side both of the gods and of the demons.

As one-fifteenth of 360° is 24°, the value of earth’s obliquity given in Sūrya Siddhānta is indeed 24°. Oak and Bhaty conclude from this value that this observation was made either in 2900 BCE or 12,000 BCE [1].

When we compared the obliquity of the Earth’s axis for years 2900 BCE and 12000 BCE, with the hope to distinguish between the two pairs in the context of the value of obliquity reported in the Sūrya-siddhānta, to our dismay, we realized that the Earth’s obliquity was indeed 240 in the year 2900 BCE and 12000 BCE!

The obliquity of earth’s axis can be calculated from the following equation [16]:

ε = 23° 26′ 21.448″ − 4680.93″ t − 1.55″ t**2 + 1999.25″ t**3 − 51.38″ t**4 − 249.67″ t**5 − 39.05″ t**6 + 7.12″ t**7 + 27.87″ t**8 + 5.79″ t**9 + 2.45″ t**10

where ε is obliquity and t is multiples of 10,000 Julian years from J2000.0 (year 2000 CE). Based on this equation, the obliquity was 23.62° in 580 CE, 24.01° in 2,900 BCE and 24.05° in 12,000 BCE. Though the formula is valid for 10,000 years from present [17] i.e. 8,000 BCE, we will assume it can be extended to 12,000 BCE.

So we have evidence that the obliquity was 24° according to Sūrya Siddhānta and 24.01° in 2,900 BCE and 24.05° in 12,000 BCE according to modern estimates. Can we conclude that Sūrya Siddhānta was written or updated in 2,900 BCE or 12,000 BCE? Simple answer is no because the obliquity was 23.62° in 580 CE and the editors of Sūrya Siddhānta could either have rounded it to 24° or the measurements at that time were not accurate enough and the astronomers of that time measured the obliquity to be 24°. Both these possibilities must be discounted before considering the dates of 2,900 BCE or 12,000 BCE. Oak and Bhaty don’t refute either of these possibilities and insist that obliquity has to be taken as exactly 24°. Narayanan has also insisted that Sūrya Siddhānta data has to be taken as exactly 24° [18]. However, the argument is based on accuracy of sine tables and not on the accuracy of measurements. In the same paper, Narayanan has dated Sūrya Siddhānta to 7300–7800 BCE based on computer simulation of Sūrya Siddhānta data. This date does not match the date of 2,900 BCE from the obliquity data so Narayanan has proposed multiple updates to Sūrya Siddhānta [18]. This article is not about refuting the paper by Narayanan, so I will get back to the work by Oak and Bhaty.

Oak says in his presentation [reference 3 at t = 16:40 to 16:55] that if authors of Sūrya Siddhānta wanted to say 24.1°, they had the ability to do so. Well, ability to write 24.1° instead of 24° no way implies that they had the capability to make such fine measurement. To make that distinction, Oak and Bhaty have to give proof of the accuracy of the value given in Sūrya Siddhānta. They need to give information about what instrument was used and how it was used. Oak and Bhaty provide no such details. Instead, Oak says in his presentation [reference 3 at t = 14:30 to 16:30] that Sūrya Siddhānta has a chapter on how to make sophisticated astronomy instruments and how Burgess dismissed them as flights of fancy. That is not enough when Oak and Bhaty present a date for Sūrya Siddhānta that goes far beyond the accepted date of not only Sūrya Siddhānta but the beginning of human civilization itself. Oak and Bhaty need to give exact reference in Sūrya Siddhānta about the instrument used to measure obliquity and not just any instrument that was used for other purpose. Oak and Bhaty also need to give exact reference in Sūrya Siddhānta where the method to use this instrument for measuring obliquity is given. I am willing to be enlightened by Oak and Bhaty as I have not found mention of any sophisticated instrument to measure obliquity in Sūrya Siddhānta. I believe that the obliquity was measured by the simplest of instruments, a gnomon (Śaṅku), which is basically a vertically placed straight rod. Sūrya Siddhānta 3.1–2 describes the placement of gnomon and Sūrya Siddhānta 3.8 provides the relationship between gnomon height, shadow length and hypotenuse. This in combination with sine tables could be used to measure obliquity by performing shadow measurements on solstices and equinoxes as described on this website [19]. With this kind of measurement, it is difficult to accept that the value of 24° given in Sūrya Siddhānta is very accurate for its time. Either the measured value has been rounded to 24° or the measurements at that time were not accurate enough and the astronomers of that time measured the obliquity to be 24°. Even if it was accurately 24 degrees, it is still explained by 2,900 BCE and there is no need to suppose that measurement was done in 12,000 BCE. This brings us to the third and final astronomical observation cited in support of 12,000 BCE date of Sūrya Siddhānta.

4. Aphelion and perihelion

Oak and Bhaty claim that Sūrya Siddhānta 12:46 can be dated to 12,000 BCE. The text is as follows:

atyāsannatayā tena grīṣme tīvrakarā raveḥ |

devabhāge surāṇāṃ tu hemante mandatānyathā ||

Oak and Bhaty translate it as [1]:

The sun is the closest to the Earth during Grishma which causes Sun’s rapidness when in Deva Bhaga i.e, Northern Hemisphere but farthest from the Earth during Hemanta which causes Sun’s slowness otherwise.

English translation by Burgess is as follows [20]:

Hence, owing to his exceeding nearness, the rays of the sun are hot in the hemisphere of the gods in summer, but in that of the demons in winter: in the contrary season, they are sluggish.

Śrīvāstava also translates this verse as sun’s rays being very hot in summer due to exceeding nearness and milder in Hemanta due to being far [21]:

The translations by Burgess and Śrīvāstava are significantly different from the translation provided by Oak and Bhaty. Again, Oak and Bhaty fail to mention the accepted version and present their version as the accepted version.

Furthermore, Śrīvāstava also says that Sūrya Siddhānta is wrong in claiming that sun was near in summer [21]:

As stated earlier, Oak and Bhaty are aware of this explanation proposed by Śrīvāstava in his scientific commentary on Sūrya Siddhānta as they have quoted his commentary. Again, Oak and Bhaty chose not to disclose this critical information to readers.

Anyway, accepted interpretation is that Sūrya Siddhānta says that it is hotter in summer because sun is near in summer. Oak and Bhaty claim that Sūrya Siddhānta says sun is moving faster in summer while sun is near in summer. Oak and Bhaty then go on to claim that authors of Sūrya Siddhānta knew of Kepler’s law in 12,000 BCE [1]. Well, if sun was moving faster in summer according to Sūrya Siddhānta, then where is the data in support of it? Does Sūrya Siddhānta say what was the speed of sun in summer and by how much it differed in winter? Forget about speed, did authors of Sūrya Siddhānta even have a good estimate of the distance between sun and earth? This is critical to the thesis proposed by Oak and Bhaty because they take the claim of sun being nearer in summer as true instead of a misunderstanding.

Oak and Bhaty’s thesis is based on the phenomenon of Apsidal precession. The apsides are the two extreme points in the orbit of a rotating body, the closest point from its primary body being called periapsis and the farthest point being called apoapsis. For earth as rotating body and sun as primary body, these points are called perihelion and aphelion. Apsidal precession is the rotation of the imaginary line connecting perihelion and aphelion around the Sun. Apsidal precession and the precession of the Earth’s axis combine to create a cycle of 21,000 years during which aphelion and perihelion move with respect to solstices and equinoxes [22]. As the seasons are related to solstices and equinoxes, they move with respect to apsides as shown in Figure 7.

Figure 7: Apsidal precession and the seasons. Image credit: Krishnavedala/Wikimedia commons 3.0 license [https://commons.wikimedia.org/wiki/File:Precession_and_seasons.svg].

The key point is that seasons are not determined by how close the sun is to earth at a given point instead seasons are determined by the earth’s tilt towards the sun. Even more important point is that we know that but the authors of Sūrya Siddhānta didn’t. Instead of recognizing the error made by authors/editors of Sūrya Siddhānta, Oak and Bhaty use the erroneous observation to claim a date of 12,000 BCE for Sūrya Siddhānta when sun was nearer to earth during summer compared to today when sun is nearer to earth during winter. Even today many people believe that earth is closer to the sun during summer according to NASA [23]:

Many people believe that Earth is closer to the sun in the summer and that is why it is hotter. And, likewise, they think Earth is farthest from the sun in the winter.

It is easy to show that the statement of Sūrya Siddhānta is based on erroneous reasoning rather than actual measurement of sun’s distance from earth. Earth’s orbit is nearly circular. According to modern astronomy, at the time of perihelion, distance is 91,402,500 miles (147,098,070 km) and at the time of aphelion, distance is 94,509,100 miles (152,097,700 km) [24]. The difference is only 3.4 %. Were the astronomers of that time able to make measurements to this accuracy? According to Sūrya Siddhānta 12.86, the distance of sun from earth is 4,331,500 yojana [25]. The value of yojana in modern units has varied from 4.5 to 9.0 miles [26]. To give the benefit of doubt, we will use the maximum value. At 9 miles to 1 yojana, the distance of sun from earth comes to 38,983,500 miles according to Sūrya Siddhānta. This is 42.65% of the value when earth is nearest to sun at perihelion. If the measurement of distance is so poor then how could the astronomers of the time of Sūrya Siddhānta make a distinction between the distances during summer and winter that vary by only 3.4 %? Thus it is clear that what Oak and Bhaty present as a proof of 12,000 BCE date of Sūrya Siddhānta is in reality a result of a misconception that is prevalent even in our times.

5. Conclusions

Oak and Bhaty’s proposed astronomical dating of Sūrya Siddhānta to 12,000 BCE has been critically analyzed. All three astronomical observations in support of this date have been refuted. First astronomical observation involved the claim of Agastya (Canopus) being South Pole Star in 12,000 BCE. This has been shown to be false with the declination of Agastya (Canopus) being only -78° 14′ instead of being between -85° and -90° to be called a South Pole Star. Besides, a South Pole Star could never be observed from anywhere in India at any time. Second astronomical observation is the value of 24° for earth’s obliquity, which can be explained by either rounding of measured value to 24° or inaccuracy of measurement as the actual value was 23.62° in 580 CE. Third astronomical observation is the statement of the sun being nearer in summer than winter. This is a common misconception even now and is the result of not knowing that seasons are determined by earth’s tilt to sun instead of distance from earth to sun.

References

1. Oak, N.N. and Bhaty, R. (2019). Ancient updates to Sūrya-siddhānta, https://www.indiafacts.org.in/archives/ancient-updates-to-surya-siddhanta/.

2. Nilesh Nilkanth Oak & Rupa Bhaty on Surya Siddhanta at Oxford, https://www.youtube.com/watch?v=XtfKxScLFrQ.

3. Ancient Updates to Surya Siddhanta, https://www.youtube.com/watch?v=bQNhQ7wxOvA.

4. Kuppanna Sastry, T.S. (1985). Vedāṅga Jyotiṣa of Lagadha in its Ṛk and Yajus recensions. New Delhi: Indian National Science Academy, pp. 13–15.

5. ibid, p. 45.

6. Roy, R.R.M. (2019). “Sidereal Ecliptic Coordinate System of Sūrya Siddhānta”, Indian Journal of History of Science, 54(3), pp. 286–303.

7. Roy, R.R.M. (2020). Zero points of Vedic Astronomy: Discovery of the Original Boundaries of Nakshatras. Mississauga, Ontario, Canada: Mount Meru Publishing.

8. Zero Points of Vedic Astronomy. Part 6 of 8 — The Dating of Vedanga… | by Dr. Raja Ram Mohan Roy | Feb, 2021 | Medium.

9. Burgess, E. (1860). Translation of the Surya-Siddhanta: A Text-Book of Hindu astronomy, Reprinted in 1935 by University of Calcutta, p. 286.

10. Śrīvāstava, M. P. (1982). Sūrya Siddhānta, with scientific commentary, Dr. Ratnakumarī Swādhyāya Saṃsthāna, Allahabad, p. 730.

11. https://en.wikipedia.org/wiki/Pole_star

12. Bhaty, R., “Astronomical Association of Natarāja’s Dance with Apasmara and Agastya”, https://www.indiafacts.org.in/archives/cosmic-consciousness-and-astronomical-association-of-natarajas-dance-with-apasmara-and-agastya/.

13. Burgess, Surya-Siddhanta, p. 301.

14. Śrīvāstava, Sūrya Siddhānta, p. 775.

15. Burgess, Surya-Siddhanta, p. 290.

16. https://en.wikipedia.org/wiki/Axial_tilt.

17. Laskar, J. (1986). “Secular terms of classical planetary theories using the results of general theory”. Astronomy and Astrophysics. 157 (1), pp. 59–70.

18. Narayanan, A. (2010). “Dating the Sūrya Siddhānta using computational simulation of proper motions and ecliptic variations”. Indian Journal of History of Science. 45(4), pp. 455–476.

19. Estimating the Tilt of the Earth, https://open.oregonstate.education/physicsforteachers/chapter/estimating-the-tilt-of-the-earth/.

20. Burgess, Surya-Siddhanta, p. 288.

21. Śrīvāstava, Sūrya Siddhānta, p. 731.

22. https://www.universetoday.com/121101/catching-earth-at-aphelion/

23. https://spaceplace.nasa.gov/seasons/en/

24. https://en.wikipedia.org/wiki/Apsis#Perihelion_and_aphelion

25. Burgess, Surya-Siddhanta, pp. 294–295.

26. Cunningham, A. (1871). “The Ancient Geography of India”, London: Trubner and Co., pp. 571–574.

Note: April 17, 2021

Mr. Nilesh Oak and Ms. Rupa Bhaty are proponents of fantastic high chronology. Since mainstream scientists won’t bother refuting their absurd claims because they are so absurd that they don’t deserve their attention, too many very educated people are being fooled by these claims. I am trying to refute these claims in the hope that better sense will prevail. I had tagged Mr. Oak in my tweet announcing the publication of this article. Mr. Oak didn’t respond to this announcement on Twitter.

Ms. Bhaty was not tagged in this announcement on Twitter as Ms. Bhaty has blocked me.

The link was also posted in the Google group भारतीयविद्वत्परिषत् by me. Both Mr. Oak and Ms. Bhaty are members of this group. There was no reply from either of them in this group. Thus it can be assumed that Mr. Oak and Ms. Bhaty are in no position to defend their claim of Sūrya Siddhānta having been written/updated in 12,000 BCE.

I had also tagged the Public Outreach and Education Committee of the Astronomical Society of India (Astronomy outreach @asipoec) in my announcement on Twitter. I am grateful that following comment was made by the Public Outreach and Education Committee of the Astronomical Society of India:

More about the author

I am a seeker in search of the true history and heritage of India. I have strong scientific background (B.Tech. in Metallurgical Engineering from Indian Institute of Technology, Kanpur and Ph.D. in Materials Science and Engineering from The Ohio State University, USA) and a deep interest in ancient Indian texts. My work on Indology spans three different fields: cosmology, astronomy, and history.

Email: rajarammohanroy108@gmail.com

Next: Sushruta Sanhita was NOT written over 7,500 years ago: Refutation of Nilesh Oak’s dating of Sushruta to earlier than 5,561 BCE

Vedic Scholar, Materials Scientist, Author of books on Vedic Astronomy, Jain Astronomy, and Ancient Indian History