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 (chhāya graha) with no tangible form, yet it exerts profound karmic influence. In Vedic mythology, Ketu and Rāhu originated from the demon Svarbhānu, who was beheaded by Viṣṇu during the churning of the ocean (Samudra Manthana). According to the Mahābhārata (Ādi Parva 19) and the Bhāgavata Purāṇa (8.9.25-26), the head became Rāhu and the tail became Ketu.

Ketu is described as a headless body or a serpentine tail, often depicted holding a flag or mace, riding a vulture or a dark chariot. Its iconography symbolizes detachment and the culmination of past actions. In the Purāṇas, Ketu is also identified with comets and meteors (dhūmaketu, meaning 'smoke-bannered'), as noted in the Skanda Purāṇa (Kāśī Khaṇḍa 46.12). Ketu is associated with spiritual liberation (mokṣa), sudden insights, and karmic release.

It governs detachment, asceticism, and occult knowledge. In Jyotiṣa Śāstra, Ketu is considered a malefic influence that can bring sudden upheavals but also profound spiritual growth. Regional traditions, especially in South India, worship Ketu in temples dedicated to the Navagraha, such as the Kumbakonam Navagraha temple. Ketu's role in Hindu cosmology is to serve as a karmic accountant, delivering the results of past deeds.

The Ketu Gayatri mantra is chanted for spiritual advancement. Ketu's influence is particularly emphasized during its transit periods (daśā) in Vedic astrology, where it can trigger both challenges and breakthroughs.

The Sanskrit word 'Ketu' (के तु) derives from the root '√cit' meaning 'to perceive' or 'to appear', with the suffix '-tu' forming a noun that signifies 'a banner', 'a sign', or 'that which is known from a distance'. In Vedic literature, 'ketu' commonly denotes a flag, a beacon, or a luminous appearance, and by extension, a comet or meteor.

The term 'dhūmaketu' (smoke-bannered) is used in the Skanda Purāṇa (Kāśī Khaṇḍa 46.12) to describe comets. As a proper noun, Ketu personifies the descending lunar node, the tail of the demon Svarbhānu.

Regional variants include 'Ketu' in Tamil and other Dravidian languages, and it is sometimes called 'A-kacha' (hairless) or 'Mūrchā' (bald) in classical texts (Dowson 1879). The name emphasizes its role as a visible celestial marker, distinct from the head (Rāhu).

Ketu's earliest attestation is in the Ṛgveda (5.40.5-9), where the demon Svarbhānu strikes the sun with darkness, and the sage Atri restores light. This myth evolves in the Brāhmaṇas and Epics. The Mahābhārata (Ādi Parva 19) narrates that during the churning of the ocean (Samudra Manthana), the asura Svarbhānu drank the amṛta and was beheaded by Viṣṇu; the head became Rāhu and the body Ketu.

The Bhāgavata Purāṇa (8.9.25-26) repeats this account. In the Purāṇas, Ketu is also identified with comets and meteors (dhūmaketu), as in the Skanda Purāṇa (Kāśī Khaṇḍa 46.12). The Yājñavalkya Smṛti (1.295) lists Ketu among the nine grahas.

By the time of the classical Jyotiṣa texts like the Bṛhat Parāśara Horā Śāstra (c. 1st millennium CE), Ketu is firmly established as a shadow planet (chhāya graha) with karmic significance. Sectarian shifts are minimal, as Ketu is universally accepted across Vaiṣṇava, Śaiva, and Śākta traditions as a celestial influence.

Ketu is depicted as a headless torso or a serpentine tail, symbolizing detachment and the culmination of past actions. In iconographic texts like the Śilpa-ratna and the Bṛhat Saṃhitā (chapter 58), Ketu is described as dark-complexioned, with two arms, 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. He is adorned with ornaments but lacks a head, or sometimes has a single face with a fierce expression.

In South Indian bronze icons, Ketu is shown as a serpentine tail with a human torso, often in a kneeling posture. In North Indian miniature paintings, he appears as a dark, headless figure riding a vulture.

The dhyāna-śloka (meditation verse) from the Navagraha stotra describes Ketu as having a smoky complexion, holding a flag and a mace, and seated on a vulture. Regional variations include the depiction of Ketu as a serpent in some folk traditions.

In Hindu philosophy, Ketu represents the descending lunar node and is considered a shadow planet (chhāya graha) with no physical form. In Advaita Vedānta, Ketu symbolizes māyā (illusion) and the karmic residues that bind the soul; its influence leads to detachment and ultimately to the realization of non-duality.

In Viśiṣṭādvaita, Ketu is a celestial being under the control of the Supreme Lord, serving as an instrument of divine justice. In Dvaita, Ketu is a distinct entity with a specific role in the cosmic order, delivering the fruits of karma.

In Śākta and Tantric traditions, Ketu is associated with the serpentine energy (kuṇḍalinī) and the chakras, particularly the mūlādhāra. The Bṛhat Parāśara Horā Śāstra (chapter 3) states that Ketu is the karaka (indicator) of mokṣa (liberation), sannyāsa (renunciation), and spiritual wisdom.

It is considered both malefic and benefic: it causes material loss to turn the individual toward God. In Jyotiṣa, Ketu's exaltation is debated; the BPHS places it in Scorpio, while modern astrologers often assign Sagittarius.

Ketu appears in Bharatanatyam and Odissi dance repertoires as part of the Navagraha nritya, where dancers depict the nine planets through specific mudras and movements. In Carnatic music, the Navagraha kritis (e.g., by Muthuswami Dikshitar) include a composition for Ketu, such as 'Ketuṃ kāmayāmi' in the rāga Śaṅkarābharaṇam. In Hindustani classical, Ketu is invoked in dhrupad and khyal compositions.

In painting, Ketu is depicted in Tanjore and Mysore school Navagraha panels, often as a headless torso. In South India, temples like the Navagraha temple at Kumbakonam have a separate shrine for Ketu. In folk traditions, Ketu is worshipped to alleviate the effects of snakebite and poisons.

The Ketu Gayatri mantra is chanted for spiritual advancement. Beyond India, Ketu is recognized in Balinese Hinduism as part of the Navagraha, and in Thai astrology as 'Ketu' (พระเกตุ). In Japanese Buddhism, the nine luminaries (kugyō) include Ketu as 'Keito' (計都), though with different iconography.