Rahu and Ketuin scriptures, astronomy and astrology

 

 Rajesh Kochhar

Mathematics Department Panjab University Chandigarh

rkochhar2000@gmail.com

16-Jan-2017

• Ever since human beings learnt to walk upright, they have looked at the sky and wondered. The sky has remained the same but its meaning has been changing.

• Today, the Universe is a mere object of study. We look at it as if from the outside. But, things were different in earlier times. People believed they were special in the eyes of the Creator and the cosmic environment was a link between them and the Creator.

• In a geo-centric, anthropocentric Universe, the Creator would surely communicate with the Earthians. The only way he could send his messages would be through the moving objects in the sky.

• The seven geocentric planets (graha) moved in predictable orbits. They thus represented cosmic order and were a source of comfort.

• In contrast, phenomena like meteors and comets that appeared without warning were classified as utpata, portent or calamity.

• Earlier, eclipses were also classified as utpata. As we shall see, even though in course of time their cause came to be understood, the fear associated with them did not disappear.

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Rahu

• Internet is a great source of information. It is a still greater source for disinformation.

• Contrary to what is mentioned on-line, Rahu does not figure in the Rigveda. In Rv (5.40:5-9) , the demon (asura) is named Svarbhanu. He pierces the Sun. The Sun in turn appeals to Atri.

• Through his praise and adoration of the Gods, Atri causes Svarbhanu’s magic arts to vanish.

• What Atri probably did was to chant mantras while the eclipse lasted.

• The Rgvedic description is significant. An eclipse was seen as the demon’s work in disrupting the cosmic order. Propitiation was needed to restore that order.

• The Atris were prominent contributors to the Rgveda. The whole of the fifth mandala is authored by them. The passage quoted above is mentioned and embellished at a number of places in the early Brahmana literature: Tandya, Gopatha, Shatapatha, and Sankhayana. ( For simplicity, I have omitted exact references)

• Svarbhanu’s career as an asura did not last very long. Atharvaveda (19, 9-10) for some reason renames the demon as Rahu.

• It is noteworthy that the authors of Atharvaveda did not consider themselves bound by the nomenclature employed in Rv.

• For some time both the names Svarbhanu and Rahu continued to be in use, but eventually Rahu prevailed.

• The name Svarbhanu was destigmatized so much so that a son of Lord Krishna was named Svarbhanu.

-• The Rahu legend was incorporated into Buddhist

literature as well. The Pali Buddhist sources refer to the moon and the sun freeing themselves from the clutches of Rahu by invoking Buddha’s name .

Ketu• Rigveda (1.50.1-9), and following it the

Atharvaveda (13.16-24), employ Ketu to mean ray of light. More typically Ketu meant combination of fire and smoke. Av (19.9.10) refers to Dhumaketu as an epithet of mrtyu [death]. It either means a comet or literally as “smoke-bannered” to the smoke rising from a funeral pyre.

• Av (11.10.1-2, 7) uses Ketu in the plural, as arunah ketavah [ruddy Ketus]. Here the reference seems to be to comets or meteors. Varahamihira’s Brihatsamhita, composed in 6th century CE but containing much older material, quotes a still earlier astronomer Garga on a class of 77 comets, called Aruna, which are dark red in colour.

Lunar nodes• Mathematical theory of eclipses was propounded in

India in 499CE by Aryabhata (born 476 CE) in his influential Siddhantic treatise simply known as Aryabhatiyam.

• Solar and lunar eclipses occur when the moon is at either of its orbital nodes. These nodes move in a direction opposite to that of the planets and complete an orbit in the rather short period of 18.6 years.

• One would have thought that at this stage it would have been declared that the cause of the eclipses was understood, and we did not need demons any more.

• This did not happen. Instead, demons now came by appointment.

Mathematical theory of eclipses was

immediately taken note of in astrological literature, which classified the two nodes as planets, implying that they were now amenable to mathematics. Since they were hypothetical they were dubbed shadow planets.

• Varahamihira (died 587 CE) was a junior contemporary of Aryabhata and a follower. He is the author of many books. While quoting him, it is important to mention the actual text.

• In Brihajjataka (2.2-3) he names the ascending node as Rahu and the descending node as Ketu and includes them in the list of planets, thus introducing the concept of nine planets or navagraha.

• The two nodes are 180 degrees apart so that specifying one automatically fixes the other. It would thus have sufficed to include just one of them. Both the nodes were separately listed no doubt to bring the planetary number up to nine which was considered sacred.

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• Rahu was already associated with eclipse. Naming the ascending node after it was understandable.

• But why was the other node called Ketu? We do not know, but my guess is this.

• In earlier times, the space between the sky and the earth was completely described by three terms: planets (graha), comets and meteors (Ketu), and eclipses (Rahu). When the twin lunar nodes were brought into the picture, it was natural to name one as Rahu. I think, Ketu was given a new role so that celestial movements could still be described in three words, as before.

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Puranic Rahu and Ketu

• There are two distinct stages in the Puranic treatment of eclipses.

• (i)If the demon Rahu devours the sun or the moon to cause an eclipse, how do they become visible again? The answer is provided by the well - known story samudramanthana (churning of ocean), described in Mahabharata, Vishnupurana and elsewhere. In the story, the demon Rahu’s head is chopped off, which survives. It is the Rahu head which causes an eclipse.

• Since the rest of the body is missing, there is an escape route for the sun and the moon so that eclipse can occur again and again.

• (ii)At this stage there was no use for the head-less body. The torso would be kept in reserve till the introduction of the navagraha when the headless body would be identified with planetary Ketu.

• The ‘first surviving depiction’ of demonic Rahu occurs in a relief of the ‘Churning of the Ocean’ carved over the façade of the doorway of cave-temple number 19 at Udayagiri in the Vidisha district of Madhya Pradesh, which can be dated to about 430-450 CE. ( Note that it is before Aryabhata.)

• Earliest known representations of Rahu as a planetary deity are those on two stone lintels, 100cm by 20cm, originally from the villages of Nachna and Kuthara in the Panna district in the Bundelkhand region of Madhya Pradesh, most likely sculpted during the reign of the Uchchakalpa king Jayanatha (r. ca. A.D.490-510)”.

If the assigned dates be correct, it is remarkable that Rahu’s planetization occurred within a decade of Aryabhata’s theory. Ketu as a planetary deity appears in about 600 CE or a little later, in Uttar Pradesh. In the eastern state of Orissa, Ketu was not counted in until the tenth century, which thus had only eight grahas till then. One wonders whether it was from Orissa that Rahu as Yahu travelled to Burma as one of the eight nats (spirits).

• Aryabhata does not use either Rahu or Ketu; he and following him many others refer to a node as pata. Brahmagupta (b.598CE) in his long career displays signs of intellectual evolution.

• Taking a position contrary to Aryabhata, he in his Brahmasphutasiddhanta, prepared in 628 CE, expresses his faith in the demon Rahu as the cause of eclipse.

• His later text, Khandakhadyaka (665 CE), however, calculates eclipses in a matter-of-fact way employing the technical term pata and without naming Rahu or Ketu.

• The 689 CE astronomical handbook Karanaratna by Devacharya uses Rahu to denote the eclipse shadow as well as the ascending node. Significantly, at one place the latter is called Rahumukha (Rahu head).

• A tersely written basic astronomical text will have no reason to mention Ketu. As comet, meteor or the like Ketu lay outside the scope of theory while as descending node it would be redundant once the ascending node Rahu or pata was mentioned.

• The imagery and iconography of Ketu have been more difficult to conceptualize. While Rahu has been well-defined since the days of the samudramanthana story, Ketu had in the sixth century CE the eclipse role thrust upon him in addition to the cometary.

• In later Iranian (and Arabic) mythology the ascending node Rahu and the descending node Ketu become the head and the tail of the dragon Al –Djawzahr. Ketu as comet is not forgotten; he figures as al-Kayd .

• Rahu and Ketu as part of mathematical astronomy were introduced into China during the Tang dynasty (618-907CE), but with modified meaning. While Rahu was retained in the sense of the lunar ascending node, Ketu was used as a designation for lunar apogee.

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• The tradition of eclipse calculation has continued uninterrupted till relatively recent times, even though only a small number of practitioners were able to do so. A copper plate inscription tells us about the grant of a village by the Kalachuri king Ratnadeva II to an astronomer , Jagannatha by name, for correctly predicting the lunar eclipse of 1128CE. He was rewarded where other astronomers in the court had failed.

• Seven centuries later, a Pondicherry-based traditional astronomer calculated for the benefit of John Warren the lunar eclipse of 1825 May 31-June 1, with the help of shells, placed on the ground, and from tables memorized “by means of certain artificial words and syllables”. The results were remarkably accurate for the time:

• There was an error of +4 minutes for the beginning, -23 minutes for the middle and -52 minutes for the end .

• Traditional almanacs still use old algorithms for their planetary position calculations, but have taken to using modern methods for calculating eclipses as a concession to the greater time consciousness of the present times.

• To sum up, the terms Rahu and Ketu have been continuously in use since the early Vedic times, but their meaning has not remained static.

• Before 499 CE, Rahu is a demon while Ketu denotes phenomena like comets and meteors. There is no connection between the two.

• After 499 CE, Rahu and Ketu become part of the navagraha, while in addition Ketu continues to be used in the old sense also.

• While interpreting old references to Rahu and Ketu, we must keep in mind the temporal context. Pre-499CE mention of Rahu and Ketu cannot be related to navagraha, because the concept did not exist then.

• To sum up• There is an interesting interplay between

scriptures, astronomy and mythology. Astronomy, even while advancing as an intellectual discipline, wished to maintain links with the scriptures. Mythology on its part did not remain frozen. When new, scientific discoveries came to be made, mythology was modified to take note of that. //

Thank

you