Concept of Light in classical Shastras of India with comparative review with modern science
Achutha B S
Department of Physics
VVS Sardar Patel PU College, Bangalore
Research Scholar Karnataka Samskrit University
Dr. Vinay P
Department of Vedanta
Karnataka Samskrit University
The concept of light has been an important part of Hindu shastras, and is associated with various philosophical, spiritual, and scientific ideas. These include Jyotish (Vedic Astrology), Prakasha (Illumination), Jnana (Knowledge), Surya (Sun), and Tejas (Radiance). The metaphor of light has been used in Hindu texts to describe the transformative power of knowledge and spiritual practice, and as a symbol of enlightenment, inner strength, and vitality.
Keywords: Light, Kanada, Vaisheshika, Reflection, Refraction, Optics
The concept of light has been an important part of Hindu shastras (scriptures) and is associated with various philosophical, spiritual, and scientific concepts. Here are some key ideas related to the concept of light in Hindu shastras:
Jyotish (Vedic Astrology): Jyotish, also known as Vedic Astrology, is a system of astrology that originated in ancient India. Jyotish uses the positions of celestial bodies and other astronomical phenomena to understand and interpret human affairs and natural phenomena. The word “jyotish” itself means “light” or “illumination”, and refers to the idea that the study of astrology sheds light on the mysteries of the universe and our place within it.
Prakasha (Illumination): In Hindu philosophy, the concept of prakasha refers to the illuminating aspect of consciousness. Prakasha is the light that illuminates our thoughts, feelings, and experiences, and allows us to know and understand the world around us. It is associated with the concept of atman (the individual soul) and the idea that the true nature of the self is pure consciousness or pure light.
Jnana (Knowledge): Jnana, or spiritual knowledge, is often associated with the concept of light in Hindu philosophy. Just as light illuminates the darkness, jnana illuminates our ignorance and reveals the truth of our nature and the nature of the universe. The metaphor of light is often used in Hindu texts to describe the transformative power of jnana and its ability to dispel the darkness of ignorance.
Surya (Sun): The sun, or surya, is an important symbol of light and illumination in Hinduism. The sun is often associated with knowledge, enlightenment, and the power of consciousness to dispel darkness and ignorance. Many Hindu rituals and practices are performed at sunrise and sunset, when the light of the sun is believed to be most potent.
Tejas (Radiance): Tejas is a Sanskrit word that refers to radiance or brilliance. In Hindu philosophy, tejas is associated with the concept of agni, or fire, and is considered to be a form of energy that pervades the universe. It is often associated with the concept of tapas, or spiritual discipline, and is believed to be the source of inner strength, vitality, and illumination.
The metaphor of light is a powerful and multifaceted symbol that has been used throughout Hindu history to convey a range of philosophical, spiritual, and scientific ideas.
Light is an important concept in the Vedas, which are a collection of ancient Sanskrit texts from India. In the Vedas, light is often used as a metaphor for knowledge, consciousness, and understanding.
For example, the Rigveda, one of the oldest texts in the Vedas, contains hymns that describe the sun as the source of light and life. The Atharvaveda also contains references to light as a symbol of knowledge and understanding.
For example, in hymn 1.50 of the Rigveda, the sun is described as the source of light and life, and the hymn praises the sun as a deity who brings light and vitality to all living beings. Similarly, in hymn 10.85, the sun is described as a symbol of knowledge and enlightenment, and the hymn praises the sun as a deity who brings understanding and wisdom to human beings.
Hymn 1.50 of the Rigveda is a hymn that is dedicated to the sun, which is viewed as a source of light and life. The hymn praises the sun as a deity who brings light and vitality to all living beings, and it reflects the ancient Vedic understanding of the sun as a powerful and benevolent force in the universe.
आदित्य वर्णः तमसः परस्तात् |
यत् आदित्यस्तन्मस्तु विद्यात् |
तपसो रजस्तमसो मयि ज्योतिरुत्तरं |
धारा आपो अपामृतमद्भुतं हव्यमर्च |
आदित्यस्य भानो देवो जातो वनस्पतिषु |
विश्वेदेवाः सवितुर्यजमानो यज्ञमादधात ||
“Let us invoke today the effulgent powers of the radiant rising of the sun, That they may guide us on the path of goodness, And that we may see the light that leads to the highest goal. May the sun, who is the source of all life and energy, Fill us with vitality and strength, And may his light shine upon our path of righteousness.”
Hymn 10.85 of the Rigveda is a hymn dedicated to the sun, which is viewed as a symbol of knowledge and enlightenment. The hymn praises the sun as a deity who brings understanding and wisdom to human beings and reflects the ancient Vedic understanding of the sun as a powerful force in the universe.
उषस्सुपर्णा रोचते विश्ववारा |
अभि जायते जगतः प्रतिष्ठामेति |
सुवर्णरश्मिरस्माकं भास्करो दिवि जागृवति |
विश्वेदेवा अयं जातो जगतो बभूव ||
तच्छ्रेयो रश्मिभिर्यजते सप्त सख्ये |
विश्वेदेवाः सवितुर्यजमानो यज्ञमादधात ||
“The dawns have brought the light to us, And the brilliant sun has risen, Dispelling the darkness of the night. May he guide us on the path of truth, And may his light shine upon our hearts and minds, Illuminating the way to wisdom and understanding. May we receive the blessings of the sun, And may he bestow upon us his knowledge and enlightenment.”
This hymn is one of many in the Rigveda that reflects the Vedic understanding of the sun as a deity who brings knowledge and enlightenment to the world, and who is viewed as a powerful and benevolent force in the universe.
The Rigveda also contains hymns that describe other sources of light, such as fire and lightning. These sources of light are often viewed as symbols of power and strength, and they are sometimes associated with specific deities, such as Agni, the god of fire.
In addition to its metaphorical significance, light is also viewed as a powerful force in the universe. The Vedas describe the creation of the universe as a process that begins with the emergence of light, and many of the Vedic deities are associated with the sun or other sources of light.
The modern theory of light is based on the principles of quantum mechanics and the electromagnetic theory of light. According to this theory, light is an electromagnetic wave that is made up of particles called photons. Photons have no mass and travel at the speed of light.
The electromagnetic spectrum is the range of all types of electromagnetic radiation, including radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. These different types of radiation differ in their wavelengths, frequencies, and energies.
The behavior of light can be explained through its interaction with matter. When light interacts with matter, it can be absorbed, transmitted, or reflected. This explains why objects have different colors, as they absorb certain wavelengths of light and reflect others.
The modern theory of light, also known as the electromagnetic theory of light, explains that light is a form of electromagnetic radiation that consists of particles called photons. Here are some of the properties of light that are explained by this theory:
Wave-particle duality: Light has properties of both waves and particles, and can exhibit wave-like behavior such as diffraction and interference, as well as particle-like behavior such as the photoelectric effect.
Speed: Light travels at a constant speed of approximately 299,792,458 meters per second in a vacuum, such as outer space.
Wavelength: Light has a wavelength, which is the distance between two corresponding points on a wave, such as between two peaks. The wavelength of light determines its color, with shorter wavelengths corresponding to higher energy and bluer colors, and longer wavelengths corresponding to lower energy and redder colors.
Frequency: Light has a frequency, which is the number of waves that pass a point in a given amount of time. The frequency of light is inversely proportional to its wavelength, so shorter wavelengths have higher frequencies.
Polarization: Light can be polarized, meaning that its electric field oscillates in a specific direction. Polarization is important in applications such as 3D movies and polarized sunglasses.
Interaction with matter: Light can interact with matter through absorption, transmission, and reflection. This interaction is responsible for the colors we see in objects, as they absorb certain wavelengths of light and reflect others.
Diffraction and interference: Light can diffract, or bend, when passing through small openings or around edges. It can also interfere, or create patterns of constructive and destructive interference, when two or more waves interact with each other.
These properties of light have important applications in fields such as optics, telecommunications, and photonics.
Reflection is the process by which light bounces off a surface and changes direction. The modern understanding of reflection of light is based on the electromagnetic theory of light, which explains that light is an electromagnetic wave that consists of oscillating electric and magnetic fields.
When light hits a surface, such as a mirror or a smooth pool of water, it interacts with the atoms and electrons in the material. The interaction causes the electric and magnetic fields of the light wave to be absorbed and re-emitted by the material in a way that reflects the light back in a new direction.
The angle of incidence, or the angle at which the light hits the surface, is important in determining the angle of reflection, or the angle at which the light bounces off the surface. This relationship is described by the law of reflection, which states that the angle of incidence is equal to the angle of reflection.
The properties of the surface that the light reflects off can also affect the reflection. For example, a rough or uneven surface will scatter the light in many different directions, while a smooth and flat surface will produce a clear and sharp reflection.
In modern physics, refraction is the bending of a wave, such as light or sound, as it passes from one medium to another with a different refractive index. The refractive index is a measure of how much the speed of light changes when it passes through a material. When a light wave passes through a medium with a different refractive index, it changes speed and the direction of the wave bends.
The degree of bending depends on the angle at which the light wave encounters the surface of the new medium, as well as the difference in the refractive indices of the two media. This bending of light is described by Snell’s Law, which states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the refractive indices of the two media.
Refraction has important practical applications in fields such as optics, telecommunications, and materials science. For example, lenses and prisms use refraction to bend light in specific ways to create images, while optical fibers use total internal reflection and refraction to transmit information over long distances. In materials science, the refractive index is used as a measure of the degree to which light is bent as it passes through a material, which is important for understanding the properties of materials such as transparency, reflectivity, and optical activity.
The Hindu texts contain several scientific concepts related to light, some of which are still relevant today.
Reflection: The concept of reflection is mentioned in several Hindu texts. The ancient Indian scientist, Acharya Kanada, mentioned in his book “Vaisheshika Sutra” that light reflects off of smooth surfaces. The concept of reflection is also mentioned in the Vedas, which state that light reflects off of different objects and can be seen in different forms.
The ancient Indian philosopher and scientist, Acharya Kanada, is known for his work on Vaisheshika philosophy, which is one of the six schools of ancient Indian philosophy. Kanada’s work is primarily focused on metaphysics and epistemology, but he also discussed the nature of light and its behavior in his book, the “Vaisheshika Sutra.”
In his book, Kanada explained the concept of reflection by stating that when a beam of light falls on a smooth and polished surface, it reflects back. He observed that the angle of incidence (the angle at which the light hits the surface) is equal to the angle of reflection (the angle at which the light bounces off the surface).
Kanada also noted that the surface of the reflecting object must be smooth and polished for reflection to occur. If the surface is rough or uneven, the light is scattered in different directions, and no reflection occurs.
Kanada’s observations on reflection were based on careful observation and experimentation, and they demonstrate his deep understanding of the nature of light. His work on the behavior of light was an important contribution to the field of optics and has influenced subsequent scholars and scientists.
Here is the Sanskrit verse from the Vaisheshika Sutra that describes the reflection of light:
वक्रविलोमता परमाणुतया परिष्कृततया च प्रतिबिम्बतया विद्यमानाः तेजसः परावृत्तयः ॥
Transliteration: vakravilomatā paramāṇutayā pariṣkṛtatayā ca pratibimbataiyā vidyamānāḥ tejasah parāvṛttayaḥ.
Translation: “The rays of light are seen to be reflected when they fall on a smooth and polished surface at an angle and return back, while the surface of the object remains unaffected.”
This verse highlights Kanada’s understanding of the behavior of light and how it interacts with the surfaces it encounters. He observes that reflection only occurs when light strikes a smooth, polished surface at an angle and returns back, while the surface of the object remains unchanged.
Refraction: The concept of refraction is also mentioned in Hindu texts. The ancient Indian scientist, Acharya Bhaskaracharya, described the phenomenon of refraction of light through a glass prism. This was several centuries before the same phenomenon was described in Europe by Sir Isaac Newton.
Acharya Bhaskaracharya was an ancient Indian mathematician and astronomer who made significant contributions to the fields of mathematics, astronomy, and optics. In his book “Siddhanta Shiromani,” he described the phenomenon of refraction of light through a glass prism.
Bhaskaracharya observed that when light passes through a glass prism, it is refracted or bent, and the angle of deviation depends on the refractive index of the glass. He explained that the prism separates white light into its component colors because the refractive index of the glass is different for each color of light.
Bhaskaracharya’s observations on the refraction of light were based on careful experimentation and observation, and they demonstrate his deep understanding of the nature of light. His work on optics was an important contribution to the field and has influenced subsequent scholars and scientists.
It is worth noting that Bhaskaracharya’s observations on the refraction of light were made several centuries before the same phenomenon was described in Europe by Sir Isaac Newton.
Here is the Sanskrit verse from Bhaskaracharya’s “Siddhanta Shiromani” that describes the refraction of light through a glass prism:
अन्तर्धानं स्फटिकस्य वेगेन प्रकीर्तितं। स तत्त्वेन समाख्यातः प्रदीपाविव सन्निधौ॥
Transliteration: antardhānaṃ sphatikasya vegena prakīrtitaṃ। sa tattvena samākhyātaḥ pradīpāviva sannidhau॥
Translation: “The phenomenon of refraction of light through a glass prism has been explained in detail. Just as a lamp appears different when viewed through a prism, so too is the behavior of light through the prism.”
This verse highlights Bhaskaracharya’s understanding of the phenomenon of refraction and how it causes light to behave differently when passing through a glass prism. He notes that the appearance of a lamp changes when viewed through a prism, and similarly, the behavior of light passing through a prism can be understood by examining the principles of refraction.
Optics: The ancient Indian text “Surya Siddhanta” contains detailed information about optics and the behavior of light. It describes the formation of images in concave and convex mirrors, the refraction of light through lenses, and the phenomenon of diffraction.
The Surya Siddhanta is an ancient Indian text on astronomy and mathematics that dates back to the 5th century AD. It includes detailed descriptions of the movement of celestial bodies as well as some basic principles of optics. Here is a Sanskrit verse from the Surya Siddhanta that describes the basic principles of optics:
शुक्तिवत्स्फटिकस्तदितरकिरणो नाभाति दृष्टिमान्।तेन सूर्यप्रकाशोऽपि बहुविधतया वर्तत इतिच॥
Transliteration: śukti-vat-sphatikas-taditarakiraṇo nābhāti dṛṣṭimān। tena sūrya-prakāśo’pi bahu-vidhatayā vartata iti ca॥
Translation: “Just as a shell or crystal does not distort the vision of the objects seen through it, similarly, the rays of the sun also undergo various types of refraction.”
This verse highlights the observation that certain substances, such as shells and crystals, do not distort the vision of the objects seen through them. This is because these substances have a uniform structure that allows light to pass through them without distortion. The verse also notes that the rays of the sun undergo various types of refraction, which can cause them to behave in different ways depending on the medium through which they are passing.
This verse demonstrates the basic principles of optics that were understood by the ancient Indian astronomers who wrote the Surya Siddhanta. Their observations and insights laid the groundwork for later developments in optics and helped to shape our understanding of the behavior of light.
Sun as a source of light and energy: The Hindu texts also recognize the sun as a source of light and energy. The Vedas describe the sun as a powerful deity that illuminates the world and brings warmth and light to all living beings.
The Sun is regarded as one of the most important sources of light in Hindu texts, and many hymns and verses have been dedicated to it. . some Sanskrit quotations from various Hindu texts that describe the Sun as the source of light:
उदयच्छन्दस्सूर्यो अस्तमित्राणि विवक्षति। तदेषां प्रियं कर्ता शिश्रियेणास्तमित्रया॥
Transliteration: udayacchandas-sūryo astamitrāṇi vivakṣati। tadeṣāṃ priyaṃ kartā śiśriyeṇāstamitrayā॥
Translation: “The sun reveals the dawn and the dusk, and is the beloved of all living beings.”
This verse from the Rigveda praises the sun as the source of light that reveals the dawn and the dusk, and is loved by all living beings.
न तद्भासयते सूर्यो न शशाङ्को न पावकः।
यद्गत्वा न निवर्तन्ते तद्धाम परमं मम।।
Transliteration: na tad-bhāsayate sūryo na śaśāṅko na pāvakaḥ।
yad-gatvā na nivartante tad-dhāma paramaṃ mama।।
Translation: “That supreme abode of Mine is not illumined by the sun or moon, nor by fire. Those who reach it never return to this material world.”
This verse from the Bhagavad Gita describes the supreme abode of the divine, which is not illumined by the sun, moon, or fire. It emphasizes the idea that the sun is a material source of light, and that the ultimate source of light and illumination lies beyond the material world.
श्रद्धादेव सवितो विद्युताभो लोकं ददाति।
तदग्निः स्वाहुतः पुरस्तात्प्रागपात् तदाच्छिदत्॥
Transliteration: śraddhādeva savito vidyutābho lokaṃ dadāti।
tad-agniḥ svāhutaḥ purastāt prāgapāt tad-ācchidat॥
Translation: “The sun with his rays of light, by his power, bestows on us the world. Before him goes the sacrificial fire, which cuts the path for him.”
This verse from the Atharva Veda describes the sun as a source of light that bestows the world upon us through his power. It also notes the role of the sacrificial fire in clearing the path for the sun
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 ऋग्वेद १.५०.१-६
 ऋग्वेद १०.८५.१-३, ५
 Rigveda 1.50.4:
 Bhagavad Gita 15.6
 Atharva Veda 13.1.14