Ketu

Ketu is one of the nine celestial bodies (Navagraha) in Hindu astrology, representing the descending lunar node. Unlike physical planets, Ketu is a shadow planet (chhaya graha) with no tangible form, yet it exerts profound karmic influence. Its origin is traced to the churning of the cosmic ocean (Samudra Manthana) as described in the Mahabharata (Adi Parva) and the Bhagavata Purana (Canto 8). According to these texts, the demon Rahu consumed the nectar of immortality and was beheaded by Vishnu's discus; the head became Rahu, while the severed body became Ketu.

Thus, Ketu is often depicted as a headless torso or a serpentine tail, symbolizing the culmination of karmic cycles and liberation (moksha). In the Rigveda (1.32), Ketu appears as a comet or banner (dhvaja), associated with smoke and fire, hence the name Dhūmaketu (smoke-banner). Iconographically, Ketu is portrayed with a dark complexion, riding a vulture or a dark chariot, holding a flag or mace, and sometimes a sword. The Skanda Purana describes Ketu as a fierce deity who presides over sudden upheavals, spiritual insights, and detachment from material bonds.

In Jyotisha Shastra, Ketu is considered a malefic influence, causing separation, loss, and unexpected events, but also granting wisdom, psychic abilities, and liberation from worldly attachments. Regional worship varies: in South India, Ketu is propitiated at the Kalahasti temple, while in the North, offerings are made during eclipses. Ketu's role in Hindu cosmology is to govern the karmic tail of the soul, representing past-life debts and the final release from the cycle of rebirth. The Devi Mahatmya (Chapter 5) alludes to Ketu as a force that dissolves ego and fosters spiritual evolution.

Festivals like Ketu Puja are observed to mitigate adverse effects and seek blessings for spiritual progress.

The Sanskrit word 'Ketu' (केतु) derives from the root '√cit' meaning 'to perceive' or 'to appear,' and originally signified a 'banner,' 'sign,' or 'bright appearance.' In the Rigveda (1.32.4), ketu refers to a 'banner' or 'comet,' often associated with smoke and fire, hence the epithet Dhūmaketu ('smoke-bannered'). The term later came to denote the descending lunar node in Jyotisha.

Regional variants include the Tamil 'Kētu' and the Kannada 'Kētu.' Dowson's 1879 Classical Dictionary lists alternate readings such as A-kacha ('hairless'), Aśleṣa-bhāva ('cut off'), and Mūrḍha ('bald'), reflecting Ketu's headless form. The name embodies the concept of a distant, luminous sign that marks karmic culmination.

Ketu first appears in the Rigveda (1.32.4) as a comet or banner (dhvaja) associated with Indra's slaying of Vritra. The Puranic account of Ketu's origin is narrated in the Mahabharata (Adi Parva 1.18) and the Bhagavata Purana (Canto 8, Chapter 9), where during the churning of the cosmic ocean (Samudra Manthana), the demon Svarbhanu (Rahu) drinks the nectar of immortality and is beheaded by Vishnu's Sudarshana chakra; the head becomes Rahu, and the torso becomes Ketu.

This myth establishes Ketu as a shadow planet (chhaya graha) with no physical form. The Skanda Purana (Kashi Khanda) elaborates on Ketu's role as a fierce deity presiding over sudden upheavals and spiritual insights.

In Jyotisha Shastra, Ketu is first systematically treated in the Brihat Parashara Hora Shastra (c. 1st millennium CE), where it is classified as a malefic planet governing moksha and karmic debts.

Ketu is typically depicted as a dark-complexioned, headless torso riding a vulture or a dark chariot drawn by pigeons. He holds a mace (gadā) in one hand and displays the varadamudrā (boon-granting gesture) with the other.

In some representations, he carries a flag (dhvaja) or a sword. The Skanda Purana describes Ketu as fierce, with a serpentine tail, adorned with ornaments, and sometimes shown with multiple heads.

In South Indian bronze iconography, Ketu is often portrayed as a simple serpentine tail without a human form, while North Indian miniature paintings depict him as a dark, headless figure with a crown. The Shilpa-shastra texts prescribe that Ketu's image should be placed in the southwest corner of a temple.

Regional variations include the depiction of Dhruvaketu, Chalaketu, and Dhumaketu as distinct forms. The dhyana-shloka describes Ketu as having a dark body, riding a vulture, and holding a mace and shield.

In Advaita Vedanta, Ketu represents the illusory nature of the individual self (jiva) and the karmic residues that bind the soul to samsara; its headless form symbolizes the transcendence of ego and the realization of non-duality (advaita). In Vishishtadvaita, Ketu is a subordinate deity (jiva) serving Vishnu, governing the karmic tail that leads to liberation (moksha) through surrender.

In Dvaita, Ketu is a distinct entity with a fixed role in the cosmic hierarchy, influencing human destiny through karmic justice. In Tantric traditions, Ketu is associated with the serpentine energy (kundalini) and the dissolution of duality, often propitiated for psychic powers (siddhis).

The Brihat Parashara Hora Shastra classifies Ketu as a karaka (indicator) of moksha, wisdom, and detachment. In Shakta theology, Ketu is a fierce form of the Goddess, embodying the destructive aspect of time (kala) that dissolves ego.

Commentators like Parashara and Varahamihira emphasize Ketu's role in karmic retribution and spiritual evolution.

Ketu appears in classical dance forms like Bharatanatyam and Odissi in pieces depicting the Navagraha, often as a headless figure with serpentine movements. In Carnatic music, compositions such as 'Ketu Kari' by Muthuswami Dikshitar praise Ketu's power to grant liberation.

In Hindustani music, the dhrupad tradition includes ragas associated with Ketu. In painting, Tanjore and Pahari miniatures depict Ketu as a dark, headless deity riding a vulture, while Mughal astrological manuscripts show him as a comet.

Folk traditions in South India, especially at the Kalahasti temple, involve offerings of black cloth and sesame seeds to appease Ketu. In Bali, Ketu is incorporated into the Navagraha ritual (Panca Yadnya).

In Cambodia and Thailand, Ketu appears in astrological texts as a shadow planet influencing eclipses. Festivals like Ketu Puja are observed during eclipses to mitigate malefic effects.