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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 (पञ्चमहाभूतानि)|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.<ref name=":02">Kumar, A. (2019). ''Ancient Hindu Science: its transmission and impact on world cultures''. <nowiki>https://doi.org/10.2200/S00906ED1V01Y201903ENG034</nowiki> (chapter 5)</ref>

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 (पञ्चमहाभूतानि)|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.<ref name=":02">Kumar, A. (2019). ''Ancient Hindu Science: its transmission and impact on world cultures''. <nowiki>https://doi.org/10.2200/S00906ED1V01Y201903ENG034</nowiki> (chapter 5)</ref>

== Introduction ==

== परिचयः ॥ 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.

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 (अग्निः)|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.

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 (अग्निः)|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 ==

== भारते भौतिकशास्त्रस्य स्रोतग्रन्थाः ॥ 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.

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

# [[Vedas (वेदाः)|'''Vedas''']] - They were the earliest texts that deal with the [[Srshti Siddhanta (सृष्टिसिद्धान्तः)|concepts of cosmology]], creation  of the universe and cosmic cycles. Sutra granthas specifically the [[Shulbasutras (शुल्बसूत्राणि)|Shulbasutras]] gave the fundamentals of mathematics and their application in geometry and architecture.

# [[Vedas (वेदाः)|'''Vedas''']] - They were the earliest texts that deal with the [[Srshti Siddhanta (सृष्टिसिद्धान्तः)|concepts of cosmology]], creation  of the universe and cosmic cycles. Sutra granthas specifically the [[Shulbasutras (शुल्बसूत्राणि)|Shulbasutras]] gave the fundamentals of mathematics and their application in geometry and architecture.

##'''Natyashastra''' - describes various musical instruments and their acoustical characteristics

##'''Natyashastra''' - describes various musical instruments and their acoustical characteristics

##'''Agasthya Samhita''' - describes electrical cells

##'''Agasthya Samhita''' - describes electrical cells

== Padarthas in Vaiseshika Darshana ==

== वैशेसिकदर्शने पदार्थाः ॥ Padarthas in Vaiseshika Darshana ==

The Vaiseshika school, attributed to Acharya Kanada, developed one of the world's earliest systematic classification of properties of matter and relation between them. In order to define and distinguish matter, Kanāda divides substance which is a part of all knowable reality into [[Padarthas (पदार्थाः)|padarthas]] or six categories (Vais. Sutr. 1.1.4)<ref name=":02" />

The Vaiseshika school, attributed to Acharya Kanada, developed one of the world's earliest systematic classification of properties of matter and relation between them. In order to define and distinguish matter, Kanāda divides substance which is a part of all knowable reality into [[Padarthas (पदार्थाः)|padarthas]] or six categories (Vais. Sutr. 1.1.4)<ref name=":02" />

# Substance (dravya)

# Substance (dravya)

*  

*  

=== Physical Attributes of Substance and Objects in Vaiseshika Darshana ===

=== ॥ 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.<ref name=":92">Prabhu, C. S. R. (2014) ''The Physics of Vaiseshika'' Tirupati: Sri Venkateswara Vedic University.</ref><blockquote>रूपरसगन्धस्पर्शाः संख्याः परिमाणानि पृथक्त्वं संयोगविभागौ परत्वापरत्वे बुद्धयः सुखदुःखे इच्छाद्वेषौ प्रयत्नाश्च गुणाः । वैशेषिक-१,१.६ । (Vais. Dars. 1.1.6)<ref name=":82" />

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.<ref name=":92">Prabhu, C. S. R. (2014) ''The Physics of Vaiseshika'' Tirupati: Sri Venkateswara Vedic University.</ref><blockquote>रूपरसगन्धस्पर्शाः संख्याः परिमाणानि पृथक्त्वं संयोगविभागौ परत्वापरत्वे बुद्धयः सुखदुःखे इच्छाद्वेषौ प्रयत्नाश्च गुणाः । वैशेषिक-१,१.६ । (Vais. Dars. 1.1.6)<ref name=":82" />

# शब्द - Sound

# शब्द - Sound

Gunas are also elaborated in [[Gunas or Qualities : An Ayurvedic perspective (आयुर्वेदे गुणाः)|Ayurveda]] by Acharya Chanaka and in [[Gunas in Nyaya Shastra (न्यायशास्त्रानुसारेण गुणनिरुपणम्)|Nyaya Shastra]].

Gunas are also elaborated in [[Gunas or Qualities : An Ayurvedic perspective (आयुर्वेदे गुणाः)|Ayurveda]] by Acharya Chanaka and in [[Gunas in Nyaya Shastra (न्यायशास्त्रानुसारेण गुणनिरुपणम्)|Nyaya Shastra]].

=== Air vs Space ===

=== ॥ 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.<ref name=":02" />

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.<ref name=":02" />

=== Dik (Space) and Kala (Time) ===

=== ॥ 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.<blockquote>तत्त्वम्भावेन । वैशेषिक-२,२.८ ।</blockquote>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.<ref name=":32">Basu, B. D. (Ed.). (1923). ''The Vaisesika Sutras of Kanada'' (N. Sinha, Trans.; 2nd ed.). The Panini Office. (pp.172)</ref> 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.<blockquote>इत इदमिति यतस्तद्दिश्यं लिङ्गम् । वैशेषिक-२,२.१० ।</blockquote>- That which gives rise to such (cognition and usage) as "This (is remote, etc) from this" is the mark of space.

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.<blockquote>तत्त्वम्भावेन । वैशेषिक-२,२.८ ।</blockquote>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.<ref name=":32">Basu, B. D. (Ed.). (1923). ''The Vaisesika Sutras of Kanada'' (N. Sinha, Trans.; 2nd ed.). The Panini Office. (pp.172)</ref> 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.<blockquote>इत इदमिति यतस्तद्दिश्यं लिङ्गम् । वैशेषिक-२,२.१० ।</blockquote>- That which gives rise to such (cognition and usage) as "This (is remote, etc) from this" is the mark of space.

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

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

== Universal Vedic Conceptions ==

== ॥ Universal Vedic Conceptions ==

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

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

# '''Visvajyoti or Cosmic Light''' as the principle of life, the essence of devatas and all manifestations

# '''Visvajyoti or Cosmic Light''' as the principle of life, the essence of devatas and all manifestations

# '''Ap (primaeval water)''' as the supra-sensible first cause.

# '''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.

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

=== Visvajyoti or Cosmic Light ===

=== ॥ 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 (ऋग्वेदः)|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 (ऋग्वेदः)|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.<ref name=":12">Bose, D. M., Sen, S. N., & Subbarayappa, B. V. (1971). A concise history of science in India. New Delhi: Indian National Science Academy. pp. 453-459</ref>

A striking feature of the Rigvedic texts is the attempt to discover the essence or power that is behind all manifestations. In the [[Rigveda (ऋग्वेदः)|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 (ऋग्वेदः)|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.<ref name=":12">Bose, D. M., Sen, S. N., & Subbarayappa, B. V. (1971). A concise history of science in India. New Delhi: Indian National Science Academy. pp. 453-459</ref>

=== Rta ===

=== ऋतम् ॥ Rta ===

[[Rta (ऋतम्)|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.<ref name=":12" />

[[Rta (ऋतम्)|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.<ref name=":12" />

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'''<nowiki/>'. Verma<ref name=":22" /> mentions that in Yaskacharya's Nirukta, rta has been stated to denote '''electricity'''.

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'''<nowiki/>'. Verma<ref name=":22" /> mentions that in Yaskacharya's Nirukta, rta has been stated to denote '''electricity'''.

=== Yajna ===

=== ॥ 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.<ref name=":12" />

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.<ref name=":12" />

=== Ap (Water) ===

=== ॥ 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.’<ref name=":12" />

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.’<ref name=":12" />

=== Panchamahabhutas ===

=== ॥ Panchamahabhutas ===

The Indian doctrine of five elements, or [[Panchamahabhutas (पञ्चमहाभूतानि)|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.<ref name=":12" /> 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.

The Indian doctrine of five elements, or [[Panchamahabhutas (पञ्चमहाभूतानि)|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.<ref name=":12" /> 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 ==

== ॥ Concept of Motion ==

=== Defining Motion based on Vaiseshika Principles and Prashastapada Bhashyam ===

=== ॥ Defining Motion based on Vaiseshika Principles and Prashastapada Bhashyam ===

Prashastapada in कर्मपदार्थनिरूपणम् prakarana<ref name=":102">[https://sa.wikisource.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%B6%E0%A4%B8%E0%A5%8D%E0%A4%A4%E0%A4%AA%E0%A4%BE%E0%A4%A6%E0%A4%AD%E0%A4%BE%E0%A4%B7%E0%A5%8D%E0%A4%AF%E0%A4%AE%E0%A5%8D Prashastapada Bhashyam]</ref> defines motion as the unconditional cause of conjunction and disjunction i.e., change of place of particles (संयोगविभागनिरपेक्षकारणम्)<ref name=":0">Seal, B. (1915). ''The Positive Sciences of the Ancient Hindus''. Longmans, Green and Co. (Chapter 2: Hindu ideas on mechanics pp. 129-132)</ref> and evolves a discussion of its characteristics properties.

Prashastapada in कर्मपदार्थनिरूपणम् prakarana<ref name=":102">[https://sa.wikisource.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%B6%E0%A4%B8%E0%A5%8D%E0%A4%A4%E0%A4%AA%E0%A4%BE%E0%A4%A6%E0%A4%AD%E0%A4%BE%E0%A4%B7%E0%A5%8D%E0%A4%AF%E0%A4%AE%E0%A5%8D Prashastapada Bhashyam]</ref> defines motion as the unconditional cause of conjunction and disjunction i.e., change of place of particles (संयोगविभागनिरपेक्षकारणम्)<ref name=":0">Seal, B. (1915). ''The Positive Sciences of the Ancient Hindus''. Longmans, Green and Co. (Chapter 2: Hindu ideas on mechanics pp. 129-132)</ref> and evolves a discussion of its characteristics properties.

# प्रतिनियतजातियोगित्वम् । दिग्विशिष्टकार्यारम्भकत्वं || pratiniyatajātiyogitvam | digviśiṣṭakāryārambhakatvaṃ - ability to classify into distinct types (of motion) characterized by directions of initial motion (linear, upwards, contraction, spreading etc)

# प्रतिनियतजातियोगित्वम् । दिग्विशिष्टकार्यारम्भकत्वं || pratiniyatajātiyogitvam | digviśiṣṭakāryārambhakatvaṃ - ability to classify into distinct types (of motion) characterized by directions of initial motion (linear, upwards, contraction, spreading etc)

Prashastapada defines motion as the unconditional cause of conjunctions and disjunctions i.e., a change of place of particles. He regards karma (motion) as instantaneous (क्षणिक), distinguishing it from impressed motion, momentum (vega) which is a persistent tendency (Samskara) and implies a series of motions. Accordingly, in one and the same particle there can be only one motion at any given moment, since its change of place at that moment is one and definite. Motion of a particle or object is one but from the point of view of the Observer, there may be many motions involved, e.g., a falling leaf driven by wind may have a rotatory or vibratory motion and a vertical downward motion at the same time. Here each particle of the leaf taken separately has only one motion or change of place at the same moment, but from Observer's stance, the particles have a rotatory or vibratory motion in one relation and the leaf as whole has a downward motion in another relation.<ref name=":0" />

Prashastapada defines motion as the unconditional cause of conjunctions and disjunctions i.e., a change of place of particles. He regards karma (motion) as instantaneous (क्षणिक), distinguishing it from impressed motion, momentum (vega) which is a persistent tendency (Samskara) and implies a series of motions. Accordingly, in one and the same particle there can be only one motion at any given moment, since its change of place at that moment is one and definite. Motion of a particle or object is one but from the point of view of the Observer, there may be many motions involved, e.g., a falling leaf driven by wind may have a rotatory or vibratory motion and a vertical downward motion at the same time. Here each particle of the leaf taken separately has only one motion or change of place at the same moment, but from Observer's stance, the particles have a rotatory or vibratory motion in one relation and the leaf as whole has a downward motion in another relation.<ref name=":0" />

=== Cosmic Motion ===

=== ॥ Cosmic Motion ===

In the discussion about Rta in the earlier section, 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.<ref name=":42" /> 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,  

In the discussion about Rta in the earlier section, 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.<ref name=":42" /> 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 ===

=== अण्वोः गतिशीलता ॥ 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।.<ref name=":62">Dwivedi, Kapil Dev. (2004) ''Vedon mein Vijnana (Positive Sciences in the Vedas).'' Jnanpur (Bhadohi): Vishvabharati Anusandhan Parishad. (Pages 1-37)</ref><blockquote>अग्निर् मूर्धा दिवः ककुत् पतिः पृथिव्या ऽ अयम् । अपां रेतांसि जिन्वति ॥ (Yajurveda. 3.12)<ref>Shukla Yajurveda ([https://sa.wikisource.org/wiki/%E0%A4%B6%E0%A5%81%E0%A4%95%E0%A5%8D%E0%A4%B2%E0%A4%AF%E0%A4%9C%E0%A5%81%E0%A4%B0%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A6%E0%A5%A9 Adhyaya 3])</ref></blockquote>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<ref name=":42" />

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।.<ref name=":62">Dwivedi, Kapil Dev. (2004) ''Vedon mein Vijnana (Positive Sciences in the Vedas).'' Jnanpur (Bhadohi): Vishvabharati Anusandhan Parishad. (Pages 1-37)</ref><blockquote>अग्निर् मूर्धा दिवः ककुत् पतिः पृथिव्या ऽ अयम् । अपां रेतांसि जिन्वति ॥ (Yajurveda. 3.12)<ref>Shukla Yajurveda ([https://sa.wikisource.org/wiki/%E0%A4%B6%E0%A5%81%E0%A4%95%E0%A5%8D%E0%A4%B2%E0%A4%AF%E0%A4%9C%E0%A5%81%E0%A4%B0%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A6%E0%A5%A9 Adhyaya 3])</ref></blockquote>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<ref name=":42" />

* ability to act as substratum of qualities/attributes

* ability to act as substratum of qualities/attributes

* to provide an inherent or material cause

* 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.<ref name=":112" />

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.<ref name=":112" />

=== Karma or Activity in terms of Physical Motion ===

=== कर्मलक्षणम् ॥ Characteristics of Karma or Activity ===

'''Three characteristics of Karma''' or activity defined as per Vaiseshika Sutras are<blockquote>एकद्रव्यमगुणं संयोगविभागेष्वनपेक्ष कारणमिति कर्मलक्षणम् । वैशेषिक-१,१.१७ । (Vais. Dars. 1.1.17)<ref name=":82" /></blockquote>The three characteristics are

'''Three characteristics of Karma''' or activity defined as per Vaiseshika Sutras are<blockquote>एकद्रव्यमगुणं संयोगविभागेष्वनपेक्ष कारणमिति कर्मलक्षणम् । वैशेषिक-१,१.१७ । (Vais. Dars. 1.1.17)<ref name=":82" /></blockquote>The three characteristics are

# Activity depends on substance

# Activity depends on substance

-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 [[Atman (आत्मन्)|Ātman]].

-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 [[Atman (आत्मन्)|Ātman]].

'''Kinds of Karma''': Motion in the sense of activity is of five kinds.<blockquote>उत्क्षेपणमवक्षेपणं आकुञ्चनं प्रसारणं गमनमिति कर्माणि । वैशेषिक-१,१.७ । utkṣēpaṇamavakṣēpaṇaṁ ākuñcanaṁ prasāraṇaṁ gamanamiti karmāṇi | vaiśēṣika-1,1.7 |<ref name=":82" /></blockquote>They are<ref name=":92" />

'''Kinds of Karma or गमनविशेषाः -''' Motion in the sense of activity is of five kinds.<blockquote>उत्क्षेपणमवक्षेपणं आकुञ्चनं प्रसारणं गमनमिति कर्माणि । वैशेषिक-१,१.७ । utkṣēpaṇamavakṣēpaṇaṁ ākuñcanaṁ prasāraṇaṁ gamanamiti karmāṇi | vaiśēṣika-1,1.7 |<ref name=":82" /></blockquote>They are<ref name=":92" />

* Ut-kṣepaṇa (Upward movement, upward thrust)

* Ut-kṣepaṇa (Upward movement, upward thrust)

* Ava-kṣepaṇa (Downward movement, downward thrust)

* Ava-kṣepaṇa (Downward movement, downward thrust)

* being सामान्य or generalized and विशेषवत् or specialized   

* 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.

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 ===

=== ॥ 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.<ref>Subbarayappa, B. V., & Sarma, K. V. (1985). ''Indian Astronomy: A Source-book: Based primarily on Sanskrit texts''. Nehru Centre. <nowiki>http://ci.nii.ac.jp/ncid/BA10111373</nowiki></ref>

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.<ref>Subbarayappa, B. V., & Sarma, K. V. (1985). ''Indian Astronomy: A Source-book: Based primarily on Sanskrit texts''. Nehru Centre. <nowiki>http://ci.nii.ac.jp/ncid/BA10111373</nowiki></ref>

=== Gravitation ===

=== गुरुत्वम् ॥ Gravitation ===

The movement as of a falling body is caused by gravity (गुरुत्वम्) which in the astronomical treatises of Aryabhata, Brahmagupta and Bhaskara is ascribed to the attraction (आकर्षण) the pulling force, exercised by the earth on a material body. The force of gravity may be counteracted by volition (विधारकप्रयत्नम्), as in holding up the hand, or by contact, as when a body rests on a support, or by Vega (वेग), impressed motion, as in the flying arrow which is kept from falling by the motion impressed on it.<ref name=":0" />

The movement as of a falling body is caused by gravity (गुरुत्वम्) which in the astronomical treatises of Aryabhata, Brahmagupta and Bhaskara is ascribed to the attraction (आकर्षण) the pulling force, exercised by the earth on a material body. The force of gravity may be counteracted by volition (विधारकप्रयत्नम्), as in holding up the hand, or by contact, as when a body rests on a support, or by Vega (वेग), impressed motion, as in the flying arrow which is kept from falling by the motion impressed on it.<ref name=":0" />

In the case of the flying arrow or other projectiles, however, the impulsive force that produces vega counteracts the force of the gravity; in the end, vega is lost through friction with air, and then gravity brings the arrow to the ground.<ref name=":1" />

In the case of the flying arrow or other projectiles, however, the impulsive force that produces vega counteracts the force of the gravity; in the end, vega is lost through friction with air, and then gravity brings the arrow to the ground.<ref name=":1" />

=== Vega: Inertia, Momentum and Acceleration ===

=== वेग ॥ Vega: Inertia, Momentum and Acceleration ===

A motion has been conceived as a change of place in a particle, instantaneous and incapable of producing another motion. But when motion is caused by impact (abhighata) or impelling push (nodana) it develops a samskara or persistent tendency to motion. This persistent tendency of a moving body to continue its motion has been called vega. That vega is a samskara has been clearly stated by Prashastapada. According to him, samskara is of three types<ref name=":42" />

A motion has been conceived as a change of place in a particle, instantaneous and incapable of producing another motion. But when motion is caused by impact (abhighata) or impelling push (nodana) it develops a samskara or persistent tendency to motion. This persistent tendency of a moving body to continue its motion has been called vega. That vega is a samskara has been clearly stated by Prashastapada. According to him, samskara is of three types<ref name=":42" />

* vega or momentum

* vega or momentum

* sthitisthapaka or elasticity

* sthitisthapaka or elasticity

The concept of vega closely fits in with the modern concept of momentum. Vaiseshikas accept one and the same samskara lasting till the cessation of motion. Udyotakara and other writers of the Nyaya school suppose a series of samskaras, each one generating the one that succeeds it. Nyaya view implies the modern idea of acceleration. The power of samskara diminishes by doing work against the counteracting forces and gradually when it gets exhausted, the moving body comes to rest. Thus Vega corresponds to inertia in some respects and to momentum (impressed motion) in others. It is the nearest approach to Newton's first law of motion.<ref name=":42" />

The concept of vega closely fits in with the modern concept of momentum. Vaiseshikas accept one and the same samskara lasting till the cessation of motion. Udyotakara and other writers of the Nyaya school suppose a series of samskaras, each one generating the one that succeeds it. Nyaya view implies the modern idea of acceleration. The power of samskara diminishes by doing work against the counteracting forces and gradually when it gets exhausted, the moving body comes to rest. Thus Vega corresponds to inertia in some respects and to momentum (impressed motion) in others. It is the nearest approach to Newton's first law of motion.<ref name=":42" />

== Light ==

== प्रकाशः॥ 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.<ref name=":52">Sharma, R., Kamlesh Thakkar, & Dubey, K. K. (2024). Physics in ancient Indian knowledge system. ''Journal of Technology'', 267–268.</ref>

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.<ref name=":52">Sharma, R., Kamlesh Thakkar, & Dubey, K. K. (2024). Physics in ancient Indian knowledge system. ''Journal of Technology'', 267–268.</ref>

* '''Jyotish''' uses the positions of celestial bodies and other astronomical phenomena to understand and interpret human affairs and natural phenomena.   

* '''Jyotish''' uses the positions of celestial bodies and other astronomical phenomena to understand and interpret human affairs and natural phenomena.   

# 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''')

# 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''')

# 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''')

# 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 ==

== Vedic knowledge regarding Surya ==

'''Solar Energy''': Vedic knowledge of the [[Surya (सूर्यः)|Surya]] and its energy is extensive according to Dwivedi.<ref name=":62" /> He provides the textual references to the following aspects

'''Solar Energy''': Vedic knowledge of the [[Surya (सूर्यः)|Surya]] and its energy is extensive according to Dwivedi.<ref name=":62" /> 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.

- 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 Aranyaka (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)<ref>Shukla Yajurveda ([https://sa.wikisource.org/wiki/%E0%A4%B6%E0%A5%81%E0%A4%95%E0%A5%8D%E0%A4%B2%E0%A4%AF%E0%A4%9C%E0%A5%81%E0%A4%B0%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A6%E0%A5%AF Adhyaya 9])</ref> refers two tattvas or nature of Sun's energy that exist in Surya - सूर्ये सन्तं समाहितम्

'''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)<ref>Shukla Yajurveda ([https://sa.wikisource.org/wiki/%E0%A4%B6%E0%A5%81%E0%A4%95%E0%A5%8D%E0%A4%B2%E0%A4%AF%E0%A4%9C%E0%A5%81%E0%A4%B0%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A6%E0%A5%AF Adhyaya 9])</ref> refers two tattvas or nature of Sun's energy that exist in Surya - सूर्ये सन्तं समाहितम्

# "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.

# "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.

# "अपां रसस्य यो रस:" meaning that which is the essence of the essence of Ap which in modern terms indicates Helium.

# "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 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.<blockquote>अव दिवस्तारयन्ति सप्त सूर्यस्य रश्मयः । आपः समुद्रिया धारास्तास्ते शल्यमसिस्रसन् ॥१॥<ref>Atharva Veda ([https://sa.wikisource.org/wiki/%E0%A4%85%E0%A4%A5%E0%A4%B0%E0%A5%8D%E0%A4%B5%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83/%E0%A4%95%E0%A4%BE%E0%A4%A3%E0%A5%8D%E0%A4%A1%E0%A4%82_%E0%A5%AD/%E0%A4%B8%E0%A5%82%E0%A4%95%E0%A5%8D%E0%A4%A4%E0%A4%AE%E0%A5%8D_%E0%A5%A7%E0%A5%A7%E0%A5%A8 Kanda 7 Sukta 112])</ref></blockquote>Many such concepts require further studies and exploration in terms of modern sciences.

- Sun-rays: The seven horses of Surya represent the seven rays of the sun.<blockquote>अव दिवस्तारयन्ति सप्त सूर्यस्य रश्मयः । आपः समुद्रिया धारास्तास्ते शल्यमसिस्रसन् ॥१॥<ref>Atharva Veda ([https://sa.wikisource.org/wiki/%E0%A4%85%E0%A4%A5%E0%A4%B0%E0%A5%8D%E0%A4%B5%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83/%E0%A4%95%E0%A4%BE%E0%A4%A3%E0%A5%8D%E0%A4%A1%E0%A4%82_%E0%A5%AD/%E0%A4%B8%E0%A5%82%E0%A4%95%E0%A5%8D%E0%A4%A4%E0%A4%AE%E0%A5%8D_%E0%A5%A7%E0%A5%A7%E0%A5%A8 Kanda 7 Sukta 112])</ref></blockquote>Many such concepts require further studies and exploration in terms of modern sciences.

== Electricity ==

== विद्युत् शक्तिः ॥ Electricity ==

Different kinds of electricity

Different kinds of electricity

• Vidyut (विद्युत) Generated from thunder

• Vidyut (विद्युत) Generated from thunder

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

• Shatakumbhi (शतकुंभी) Generated by hundred cells or pitchers (Kumbha’s)

• Hrdani (हृदनी) Stored electricity with portable properties

• Hrdani (हृदनी) Stored electricity with portable properties