Ancient Indian Physics (भौतिकविज्ञानम्)

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Ancient Indians contributed to the development of many concepts of modern Physics (Samskrit: भौतिकविज्ञानम्) much earlier than the advent of modern physics. The study of physics involves an understanding of the functioning, interactions and relationships between the fundamental components of the observable universe and the observable cosmos. The field of physics covers all aspects of the natural world, both at macroscopic and microscopic levels. The conception of Panchamahabhutas, or the five gross elements, to explain the diversity of nature, was the foundational aspect of Indian physical shastras. Nature consists of a variety of things – solids, water, gas, fire, and space. Space, or Akasa, is considered eternal and was created to give material objects a positive reference, a substratum, and a medium on which things exist. In modern terms it resembles the concept of an all-pervading ether medium.

Introduction

Physics deals with matter and energy and their interactions. Measurements are central to the growth of physics, and length (space), time, and mass are the three most important physical quantities, called the fundamental quantities. Most other physical quantities are generally expressed in terms of mass, length, and time. For example, speed is measured in miles per hour (or kilometers per hour) and involves a measurement of space (distance) and time.

Electricity (विद्युत), light (प्रकाशः), Heat (तापः), Mechanics (motion (गतिः) and inertia of things), Magnetism (चुम्बकत्वम्), Gravitation (गुरुत्वम्), Sound (ध्वनिः) and its transmission, and quantum physics, which comprise the subjects of modern physics have been explored in several Indian traditions along with their applications. In the Vedas, Agni represents many aspects of physics. It should be kept in mind that Vedic terminology is full of symbolism and hence the interpretations of Veda mantras have to be taken in that perspective.

Source Texts for Physics in India

There are many sources of knowledge of physics in ancient Indian texts and a wide range of topic they dealt with.

1. Vedas - They were the earliest texts that deal with the concepts of cosmology, creation of the universe and cosmic cycles. Sutra granthas specifically the Shulbasutras gave the fundamentals of mathematics and their application in geometry and architecture.
2. Upanishads - They explain interconnectedness of matter-energy, their relationship and unity, the chemical qualities such as solubility, viscosity etc.
3. Darshanas - They put forth the earliest atomic theory, defined matter, their interactions and attributes. Vaiseshika darshana elaborates the atomic theory (Paramanu), classified reality into seven padarthas and explained their characteristics.
4. Puranas - A great deal of information on light, cosmology is specifically noted in Vishnu, Vayu and Matsya puranas.
5. Vaastu shastra, Shilpa shastra - They discuss the principles of structure, geometry, acoustics, and materials.
6. Siddhanta granthas - Surya siddhanta for example describes the planetary motion, eclipses, calculation of time (concept of cyclic time, yugas, kalpas) and trignometric functions.
7. Commentaries - Astronomical texts such as Aryabhata's Aryabhatiya gave the foundational concepts such as rotational motion of earth, celestial body calculations, correct order of planetary orbits and the infiniteness of the universe. Bhaskara II's Siddhanta Shiromani deals with advanced astronomical principles, mechanics and planetary equations. A commentary of Kamasutra by Visvakarma details design of machines.
8. Other works - Many texts were lost but we find their references in major texts such as Mahabhashya, Mahabharata, Puranas, Arthashastra and Samarangana Sutradhara.
   1. Samarangana Sutradhara - Yantras or contrivances useful in creating mechanical objects such as birds, fountains are described in this text. It also describes yantras used in war machines, water-lifting instruments for agricultural uses, and time devices such as water clocks for astronomical measurements.
   2. Yantrarnava - describes physical concepts such as generation of power/energy or motion through the continuous movement of lever/pulley.
   3. Natyashastra - describes various musical instruments and their acoustical characteristics
   4. Agasthya Samhita - describes electrical cells

Padarthas in Vaiseshika Darshana

In order to define and distinguish matter, Kanāda divides matter, or substance into padarthas or six categories (Vais. Sutr. 1.1.4)

1. Substance (dravya)
2. Quality (guna)
3. Action (karma)
4. Generality (sāmānya)
5. Individuality (viśesa)
6. Inherence (samavāya)

Matter of different materials have different attributes. For example, identical sizes of iron and cotton would have different weights. Apples can have differences in their colours and yet be called apples. It is the assembly of attributes that defines matter. Maharshi Kanada describes seventeen attributes, or gunas, of matter, and each of the bhutas, or elements, has special characteristics:

• रूपरसगन्धस्पर्शवती पृथिवी । वैशेषिक-२,१.१ । Prithvi (Earth) has the attributes of color, taste, touch and smell
• रूपरसस्पर्शवत्य आपो द्रवाः स्निग्धाः । वैशेषिक-२,१.२ । Ap (Water) has the attributes of color, taste, touch, fluidity and viscidity
• तेजो रूपस्पर्शवत् । वैशेषिक-२,१.३ । Tejas or Agni (Fire) has color and touch
• स्पर्शवान् वायुः । वैशेषिक-२,१.४ । Vayu (Air) has touch
• त आकाशे न विद्यन्ते । वैशेषिक-२,१.५ । Akasa (space or ether) has no attribute of touch

Physical Attributes of Substance and Objects in Vaiseshika Darshana

In Classical (or Newtonian) Physics the role of Observer was ignored even though observation was essential. In Modern Physics, however, the role of the Observer is significant and is a critical requirement for all observations, since all observations are purely relative to the Observer. Even though Vaiseshika system deals with Classical Physics and not Quantum or Relativistic Physics, the importance of Observer was well recognized and the Observer was defined in two components: The Mind and the Self. The Self could be the actual Observer, but Self should have an active Mind, for performing observations. This could be identified as a unique contribution of Vaiseshika principles.

रूपरसगन्धस्पर्शाः संख्याः परिमाणानि पृथक्त्वं संयोगविभागौ परत्वापरत्वे बुद्धयः सुखदुःखे इच्छाद्वेषौ प्रयत्नाश्च गुणाः । वैशेषिक-१,१.६ । (Vais. Dars. 1.1.6)

Gunas (17) are the qualities or properties or attributes. They include

1. रूप or form/shape/colour
2. रस or taste
3. गन्ध or smell
4. स्पर्श or touch
5. संख्या or numbers/counting
6. परिमाणानि or various measures such as length, area, volume, weight etc.
7. पृथक्त्वं is being distinguished (to be separated)
8. संयोग is conjunction or joining (or combination)
9. विभाग is disjunction, disjoining or division
10. परत्व is being next (spatially next or temporally later or subsequent)
11. अपरत्व is being previous (spatially previous or temporally previous or earlier)
12. बुद्धयः intellects (several)
13. सुख is happiness
14. दुःख is sorrow
15. इच्छा is desire
16. द्वेष is aversion
17. प्रयत्नाः relates to efforts

The first 11 (from rupa to aparatva) are the qualities of physical substances or entities (dravya). The last 6 (from Buddhi to Prayatna) are the qualities of the Mind and Self (they are considered dravyas). Prayatna (effort) is a quality of Self while the rest of the 5 are the qualities of the mind.

The first 11 qualities mentioned above are well known as physical properties in Physics and Chemistry. Conventionally, every substance is examined for the same physical properties. Quality of counting is fundamental for any material entity. The qualities of being previous and being next are related to Space and time also. Conjunctive and disjunctive interactions are very common in Physics and chemistry wherein two or more entities or substances can be combined to form a new entity or an existing entity can be decomposed into several individual entities.

Prashastapada elaborated further on Gunas and brought in additional Gunas as follows:

1. गुरुत्व - Gurutva having weight, heaviness
2. द्रवत्व - Dravatva having liquidity or fluidity
3. स्नेह - Moisture, softness, viscidity or stickiness
4. संस्कार - trait, habit, impression
5. धर्म - Dharma or merit
6. अधर्म - Adharma or demerit
7. शब्द - Sound

Gunas are also elaborated in by Acharya Charaka in Ayurveda and in Nyaya Shastra

Air vs Space

In his attempt to clarify a difference between space and air, Kanāda used the attribute of touch, which is absent in space: “Air has the property of touch, while space does not have such a property.” While analyzing air, Kanāda concludes that "क्रियावत्त्वात् गुणवत्त्वाच्च । वैशेषिक-२,१.१२ । air is substance since it has action and attributes." Air is matter, but its non-perception in spite of being a substance is due to the non-existence of colour in it. With the non-perception of air, Kanāda defines reality beyond appearance. Not all that exists in the world is visible to human eyes. To support that air is matter, Kanāda argued that तृणे कर्म वायुसंयोगात् । वैशेषिक-५,१.१४ । breeze can move the blades of grass. Thus air, though invisible, can exert force and move things.

Dik (Space) and Kala (Time)

Vaisheshika principles approach fundamental scientific concepts in a characteristic manner. In these sutras we find the basic definitions of dravyas or categories of time and space.

तत्त्वम्भावेन । वैशेषिक-२,२.८ ।

Meaning: Time, like Existence, is One (unity), because, in spite of their multiplicity, the marks of Time, namely the cognition (example - "it is slow or late") are the same in all places and because there is no distinguishing mark like the Atman, which is Existence. Time which is said to be One, however, is manifold, hours, moments, days, days and nights, seasons and years. The reason for this is explained as due to the external condition or Upadhi - the indivisible time appears to be different according to the limit set by the movement of the Sun as well as the limit imposed by the effects of sun. The division of time as past, present and future as understood by the observer is said to be a consequence of the fact that time is a function of movement.

इत इदमिति यतस्तद्दिश्यं लिङ्गम् । वैशेषिक-२,२.१० ।

- That which gives rise to such (cognition and usage) as "This (is remote, etc) from this" is the mark of space.

Time, space, Atma and mind are the eternal or nitya dravyas and none of them are perceivable by any of the sense organs is a basic definition in Vaiseshika. Although, these four eternal entities can only be conceived by the mind, they are real existent dravyas or entities. Time, space and akasa are incapable of motion and it is only the earth, water, fire and air (the four dravyas) and mind which are capable of motion.

दिक्कालावाकाशं च क्रियावद्वैधर्म्यान्निष्क्रियाणि । वैशेषिक-५,२.२१ ।

Meaning: Space, time, Akasa and Atman (indicated by the word "Cha") are void of action because of their difference from that which possesses activity.

Space is identified through the fact that it can provide the context to describe objects as being separated spatially.

Universal Vedic Conceptions

Physical concepts in the Vedic texts show some universal features, such as

1. Visvajyoti or Cosmic Light as the principle of life, the essence of devatas and all manifestations
2. Rta or Natural Law as the transcendental and unitary principle of all motions (universal and individual)
3. Yajna as the connective dynamic principle and nucleus of all evolution
4. Ap (primaeval water) as the supra-sensible first cause.

These universal conceptions laid the foundations for newer formulations which are holistic in nature and structure.

Visvajyoti or Cosmic Light

A striking feature of the Rigvedic texts is the attempt to discover the essence or power that is behind all manifestations. In the Rigveda, the concept of the unmanifested is cosmic energy, and the manifested is cosmic light, which is referred to as Visvajyoti, a positive unitary principle, pure and sublime. One can conceive the cosmic light as the principle of life and longevity, and it is the ‘soul of all gods’ and the ‘womb’ of all created things. Sri Aurobindo explains the symbolism of Aditi as 'the boundless' or 'the unbounded'. According to the Rigveda, Aditi is the substratum (pure consciousness of infinite existence) of all that is here and beyond. Aditi is Light-Infinite, and the deities who are born of Aditi are manifestations of the Infinite Light. Mundaka Upanishad (2.20.10) refers to Brahman as the Self-Luminous Light.

Rta

Rta is the cosmic law of harmony. ‘Rta’ means ‘the course of things’, order or law, and the primal principle, which is non-temporal and cohesive. It is a natural law which even the Vedic deities have to follow; they are often described as the "guardians of rta" and "practitioners of rta" in the Rigveda (1.23.5). The natural phenomena, such as the flow of rivers, change of seasons, and day and night, are stated to be in accordance with this natural law (Rig. Veda. 4.3.8-12; 5.80.1). Aditya, or Surya, is the all-pervading light extolled as the dweller in eternal law and, eventually, the eternal law itself (Rig Veda 4.40.5). The Rigvedic seers were convinced that nature is not as heterogeneous as it seems to us and that all types of natural motions are traceable to rta, which, according to them, is self-existent and ever extending. Symbolically, rta was also conceived by the Rigvedic seers as Varuna, who was supposed to have determined the laws of the physical universe. Rta helps Indra "light up and energize the whole world" and Ushas to "illumine the universe". As eternal order, it is transcendental, signifying uniformity of nature or an ordered course in a cosmic sense.

The Vedic seers had the instinctive conviction in the natural order. They conceived the external world as an ordered whole and that its dynamic or changing phenomena were regulated by rta. Vedas state that the emergence of ṛta is the initiation of the process of creation. In the context of physical sciences, it is not far-fetched to infer that Prakriti from the state of existence (first attribute) undergoes a change by way of rajas guna (second attribute), or motion. In modern scientific language this would mean that energy at rest (Potential Energy) changed to kinetic form (Kinetic Energy) and thus the Vedic term for modern kinetic energy is ṛta. The term Kinetic Energy relates purely to motion and does not carry other meanings related to rta as in the Vedic context, i.e., rta represents motion charged with the knowledge of accomplishing some purpose.

Rta is all science, divine and is never wrong, rta is always right as Vedic language calls the divergence from rta as anṛta i.e., not ṛta.

Rta through its constant motion lays down the pattern of the cosmic law which governs, controls and maintains all creation and the entire activity, actions and re-actions, related with the same. This cosmic law is called dharma by Veda. 

Dharma is science and nothing but science an most certainly not religion in the Vedic context.

Dharma is neither any worship or a ritual; science is the knowledge of order and dharma is the order itself.

rtam ca satyam ca (Rig. Veda. 10.190.1)

Rta and satya were the successive manifestations of Prakriti after the commencement of the process of creation. While rta is the cosmic order, Satya, the Sanskrit term, is synonymous with 'Truth' in English, but in physics 'satya' denotes 'reality'. Verma mentions that in Yaskacharya's Nirukta, rta has been stated to denote electricity.

Yajna

Yajna is referred to as the navel of the universe (vishvanabhi) round which the latter turns, and as the unifying principle which expands and contracts in accordance with the happenings in the universe. For, the Rgvedic seers believed that yajna is the instrument for preserving the cycle of cosmic events in harmony. The act of yajna is for the protection of rta. It also has the connotation of dynamism too.

Ap (Water)

The famous Nasadiya Sukta in the tenth Mandala of the Rigveda, speaks of water as the supra-sensible First Cause or the primeval world-ground; and water is the first "element" to be conceived in this manner, without any mythological association. In the Brhadaranyaka Upanishad (5.5.1), it is stated: ‘In the beginning this world was just water.’

Panchamahabhutas

The Indian doctrine of five elements, or Panchamahabhutas, it must be emphasized, is a part of the philosophical ideas. In other words, it does not have an independent standing apart from its being an integrated component of the leading systems of Indian thought. It accounts for the apparently unordered, diverse world of matter and qualities. Also known as Panchabhutas (Mahabhutani), the five elements are Prithvi, Apas, Tejas, Vayu, and Akasha, are loosely translated respectively as earth, water, fire, air and a non-material ubiquitous substance. Since they are interrelated, they have to be viewed in totality.

Concept of Motion

Cosmic Motion

In the discussion about Rta, it is mentioned that Rta pertains to cosmic motion. Prakriti in motion is named rta and its transformed or condensed state is called satya in Vedic texts. Rta is derived from the root r meaning gati or motion. The concept of motion is fundamental as seen in the movement of sound waves, the speed of light rays travelling in space, the falling bodies due to gravitation,

Atoms are in a state of Motion

Rigveda and Yajurveda mention that Agni causes movement in Paramanu or Atoms (atomic motion). Energy within each and every atom makes them dynamic and active in motion (गतिशील). Energy imparts the qualities of speed, progress, expansiveness and novelty to every molecule. The Vedic term for molecules is रेतस्।.

अग्निर् मूर्धा दिवः ककुत् पतिः पृथिव्या ऽ अयम् । अपां रेतांसि जिन्वति ॥ (Yajurveda. 3.12)

The Vaiseshika theory posits that atoms possess an inherent property called parispanda (vibration or motion). Thus, motion/movement is intrinsic to matter and is the basis of all activity in the universe. Viseshika conception of matter is embodied in the term dravya (substance) whose definition criteria includes

• ability to act as substratum of qualities/attributes
• being endowed with motion (kriyatattva)
• to provide an inherent or material cause

Parispanda sometimes stands for motion molar as well as molecular, but more often for the subtle motion of atoms or molecules. The radical meaning of the term is whirling or rotary motion, a circling motion, but it may also include simple harmonic motion (e.g. vibration). All action, operation, work (Kriya, Vyapara) is ultimately traced to this form of subtle motion lodged in the atoms or in the matter-stuff.

Karma or Activity in terms of Physical Motion

Three characteristics of Karma or activity defined as per Vaiseshika Sutras are

एकद्रव्यमगुणं संयोगविभागेष्वनपेक्ष कारणमिति कर्मलक्षणम् । वैशेषिक-१,१.१७ । (Vais. Dars. 1.1.17)

The three characteristics are

1. Activity depends on substance
2. Activity does not possess any quality inherently. It is substance that possess guṇa and karma.
3. Movements cause disjunction (Vibhāga) of a substance (whole or part) from its previous position and conjunction (saṃyoga) with a new position. Thus activity brings out conjunction and disjunction.

-In a living organism, karma is initiated from within by Effort (Prayatna).

-In a non-living organism, karma is not initiated from within and needs an external agent to initiate. This is because effort (Prayatna) is a quality of the Ātman.

Kinds of Karma: Motion in the sense of activity is of five kinds.

उत्क्षेपणमवक्षेपणं आकुञ्चनं प्रसारणं गमनमिति कर्माणि । वैशेषिक-१,१.७ । utkṣēpaṇamavakṣēpaṇaṁ ākuñcanaṁ prasāraṇaṁ gamanamiti karmāṇi | vaiśēṣika-1,1.7 |

They are

• Ut-kṣepaṇa (Upward movement, upward thrust)
• Ava-kṣepaṇa (Downward movement, downward thrust)
• Ākuñcana (Contraction or flexion, pulling towards a point)
• Prasāraṇa (Expansion or extension, spreading, transmission)
• Gamana (general movements)

It is interesting to see the definition of general motion distinguished from the other four specific categories of motion. Prashastapada identified many more categories of motion as follows:

गमनग्रहणाद्भ्रमण-रेचन-स्पन्दनोर्ध्वज्वलनतिर्यक्पतननमनोन्नमनादयो गमनविशेषाः । (Prashastapada Bhashya)

While motion (gamana) can mean, in general, any type of motion, as defined in a given context, Prashastapada has identified some well known additional categories of motion that are universally observable and referred to in later sutras of Vaiseshika:

• भ्रमणम् or circular motion or rotation
• रेचनम् or gushing out or expulsion
• स्पंदनम् is the harmonic motion or beat (as in the case of heart beat or हृदयस्पंदनम्)
• ऊर्ध्वज्वलनम् or upward burning (of flame)
• तिर्यक्पतनम् or falling backwards
• नमनम् or bending forward
• उन्नमनम् rising upward

Properties of Karma: In the following sutra Kanada Maharshi describes the properties of all dravya (material entities, guna (qualities themselves) and karma (motion).

सदनित्यं द्रव्यवत् कार्यं कारणं सामान्यविशेषवदिति द्रव्यगुणकर्मणामविशेषः । वैशेषिक-१,१.८ । (Vais. Dars. 1.1.7)

The following are the general properties of dravya, guna and karma.

• Having existence (सद्)
• being अनित्यं or impermanent (temporary)
• being द्रव्यवत् कार्यं or the result or effect (of something which is a cause)
• being the कारणं or cause (of something which is a result or effect)
• being सामान्य or generalized and विशेषवत् or specialized

Prashastapada adds two more properties to the above namely अभिधेयत्व and ज्ञेयत्व i.e., naming (them) and knowing (them). It meaning being identified with a name and also being known.

Geocentrism and Rotatory Motion of Earth

The Indian traditional astronomy is essentially geo-centric and geo-static inasmuch as the Earth is considered to be a stationary sphere at the centre of the solar system. The Sun, the Moon and the planets have a motion of their own from west to east while the asterisms or the stellar sphere is considered to have their motion from east to west, as a result of which the former are supposed to fall behind the latter. This geocentric and geo-stationary view was for the first time modified by Aryabhata I who, while maintaining the geo-centric idea, conceived of a direct rotation of the Earth about its axis, and even gave a precise rate of rotation stating that the Earth rotates through an angle of one second in one prana of time.

Light

The concept of light has been an important part of Indian 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 symbol of light has been used in Indian texts to describe knowledge and spiritual practice and as a symbol of enlightenment, inner strength, transformation and energy. 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.

• Jyotish uses the positions of celestial bodies and other astronomical phenomena to understand and interpret human affairs and natural phenomena.
• 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.
• Jnana is often associated with the concept of light in Indian philosophy. Light illuminates and removes the darkness; similarly, jnana illuminates our minds and removes ignorance to reveal the truth of our nature and the nature of the universe.
• 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. Rituals and practices are performed at sunrise and sunset, when the light of the sun is believed to be most potent.
• Tejas refers to radiance or brilliance. Tejas is associated with the concept of agni, or fire, and is considered to be a form of energy that fills the universe. It is often associated with the concept of tapas, or spiritual discipline, and is believed to be the source of inner strength, energy, and illumination.

ऊर्जा तापश्च ॥ Energy and Heat

Vedic Physics describes Prakriti as the material cause of the the creation while in modern physics it is called Energy. Affected by the divine touch of Purusha, Prakriti the inert unconscious entity is set into motion, i.e., rta, and invariably follows the creative process. Characteristics of Prakriti include having eternal existence and capability of conserving itself in any of the three states of its being namely

• existence
• motion
• and transformation to any form of matter

Potential and Kinetic Energy: In many Veda mantras, Agni represents the forms of Energy. In Yajurveda

अग्निरमृतो नि धायि । (Yaju. Veda. 12.24) अग्निरमृतोऽभवद् वयोभिर् । (Yaju. Veda. 12.25)

Meaning - Agni (Energy form) is eternal and indestructible. It remains indestructible in the mortal world or jagat, due to its potential energy denoted by the term वयस्।

Earlier it was seen how Rta is understood as Kinetic Energy.

Transformation of Energy: Vedas proclaim that Agni (in the form of Energy) is One; it undergoes transformation and hence various are its names. It has the capability to all activities, hence it is called Visvakarma. Urja or energy takes many forms hence it is called Vishvarupa.

यो देवानां नामधा एक एव.. ॥३॥ (Rig. Veda 10.82.3) स्तीर्णा अस्य संहतो विश्वरूपा । (Rig. Veda. 3.1.7)

Omnipresence of Energy: All the four Vedas proclaim that Agni imparts the quality of movement or chetana and is all-pervading in every atom of the Dyulok (heavenly), Antariksha (Celestial region) and Earth. Due to this energy, there is movement, existence and transformation in every particle. Hence Agni is said to pervade the heavens and earth with the core activity of causing movement.

रोदसी भानुना भात्यन्तः ॥४॥ (Rig. Veda. 10.45.4) विश्वस्य केतुर् भुवनस्य गर्भऽ आ रोदसी ऽ अपृणाज् जायमानः । (Yajurveda. 12.23)

Power of Expansion: Yajurveda recounts the expansive quality of extreme heat (denoted by the term त्वेषः) energy in Agni, which causes the expansion of the universe/world.

अग्ने ... येनान्तरिक्षम् उर्व् आततन्थ त्वेषः स भानुर् अर्णवो नृचक्षाः ॥ (Yajurveda. 12.48)

Forms of Energy: Yajurveda talks about the "three bodies" or forms of Agni.

1. या ते अग्नेऽयःशया तनूः - Ayas (अयस्) here means dhatu or metal; Agni or Energy within the metals. The core of the earth is described as ball of metallic fire. (Terrestrial Metallic Form of Energy)
2. या ते अग्ने रजःशया तनूः - Rajas (रजस्) denotes molecules in space and the energy form is indicated by Vidyut or Electricity, thunderstorms, and hurricanes. (Atmospheric Form of Energy)
3. या ते अग्ने हरिशया तनूः - The term Hari (हरि) represents Sun and sunrays. The heat energy residing in Sun and the warmth and heat of sun all represent the heat form of energy. (Solar Form of Energy)

Interesting Vedic knowledge of Surya

Solar Energy: Vedic knowledge of the Surya and its energy is extensive according to Dwivedi. He provides the textual references to the following aspects

- सप्त आदित्या: Sapta Aditya (सप्त दिशो नानासूर्याः...), there are seven suns according to Rigveda (9.114.3) and Atharvaveda mentions that the central Surya is Kashyap, while Taittriya Aranyaja (1.7.1) gives the names of these seven suns.

- Hydrogen and Helium as the energy source: सोमेन - आदित्या बलिन: । (Atha. Veda. 14.1.2) Dwivedi refers Soma to Hydrogen from which Sun gains its energy. Yajurveda (9.3) refers two tattvas or nature of Sun's energy that exist in Surya - सूर्ये सन्तं समाहितम्

1. "अपां रसम्" meaning that which is the essence of Ap or water in a gaseous form denoted by the term "उद्वयस्" Udvayas. These in modern terms refer to Hydrogen (split from water) in a gaseous form.
2. "अपां रसस्य यो रस:" meaning that which is the essence of the essence of Ap which in modern terms indicates Helium.

- Sun spots: Rigvedic terms (Rig. Veda. 1.164.14) such as चक्षु (मंडल, घेरा) रजस् (धूल, धब्ब) indicate that Surya is associated with spots, a fact identified since early ancient times.

- Sun-rays: The seven horses of Surya represent the seven rays of the sun.

अव दिवस्तारयन्ति सप्त सूर्यस्य रश्मयः । आपः समुद्रिया धारास्तास्ते शल्यमसिस्रसन् ॥१॥

Many such concepts require further studies and exploration in terms of modern sciences.

Electricity

Different kinds of electricity

• Tadita (तडित) Generated by rubbing silk cloths

• Saudamini (सौदामिनी ) Generated by rubbing two gems

• Vidyut (विद्युत) Generated from thunder

• Shatakumbhi (शतकुंभी) Generated by hundred cells of pillars (Kumbha’s)

• Hrdani (हृदनी) Stored electricity with portable properties

• Ashani (अशनी) – Generated from magnetic rods (P. P. Hole –Machines in Samskrit Literature)

Construction of Electric Cell

It is mentioned by some scholars that Agasthya described how to make an electric battery and separate water into oxygen and hydrogen.

संस्थाप्य मृण्मये पात्रे ताम्रपात्रं सुसंस्कृतम्‌। छादयेच्छिखिग्रीवेन चार्दाभि: काष्ठापांसुभि:॥

A clay pot was covered with a clean copper plate, copper sulfate, and moist sawdust. The cathode, Mitra, and the anode, Varuna, were zinc amalgam sheets placed on top of these layers. To boost electricity, 100 Shata Kumbha jars were linked. As the reaction occurred, water split into Oxygen (pranavayu) and Hydrogen (udanavayu). In an airtight cloth, hydrogen gas was collected for aerodynamic use.

However, the shloka has been unverified at the time of compilation of this article. In the reference of the text Agastya samhita, edited by Pt. Bhavanath Jha, Acharya Kishore Kunal in his preface discussed the topic of Agasthya samhita's association with the usage and preparation of dry battery cell. He brings into context several aspects of scholarly discussions about Varuna, Pranavayu and Udanavayu that throw light on the later day interpolations and wrong attributions of electric batteries to Agastya Samhita. It was shown how Agasthya samhita deals with yoga and higher philosophical contexts and does not contain aspects of Physics. This information he mentions was posted by Chinmay Yuva Kendra in 2006 in a website, under the heading "Ancient Indian Approach to Science" as a part of Chronicles of Hinduism series.