To understand existence, it would be relevant to know about the nature of matter. Matter, either living or nonliving is made up of basic building blocks known as atoms. All atoms contain particles called electrons that carry a negative electrical charge. At the center of the atom lies the atomic nucleus which is composed of two types of particles; the proton which carries both mass and a positive electric charge, and the neutron which has about the same mass as a proton but is electrically neutral. Protons, neutrons, and electrons are the constituents of ordinary matter. But these are only three of a vast number of similar particles which differ only in a few properties such as their mass, electrical charge, and their stability against spontaneous decay. Protons, and neutrons are part of a much larger family of similar objects which are collectively called nucleons. Many of these fundamental particles are combinations of elementary particles popularly known as ‘QUARKS’. 


Any influence that causes a collection of particles to undergo some change is known as FUNDAMENTAL INTERACTION. 

All known physical interactions of matter occur through the agency of four basic physical or fundamental kinds of forces. These Four Fundamental Forces, in decreasing order of strength are, the Strong Nuclear, the Electromagnetic, the Weak Nuclear, and the Gravitational forces. Each force has a characteristic strength and a range or distance over which they can exert their effects. The Strong Nuclear force is the strongest force known in nature. Its range is about a distance of 10 to the power of(-)13 cm. It weakens rapidly with distance. The particles of the atomic nucleus are tightly bound by the Strong Nuclear force. The Weak Nuclear force is involved in nuclear decay processes and in interactions involving the fundamental particles called neutrinos. If the Strong Nuclear force between two protons is assigned a strength of 1, then the Electromagnetic, Weak Nuclear, and Gravitational forces between the same two protons have relative strengths of 10 to the power of(-)2, 10 to the power of(-)5, and an incredibly small 10 to the power of(-)40. Thus the effect of Gravitational force on interactions among particles of atomic size is negligible. The Electromagnetic attractive force between a proton and an electron is several (10 to the power of40) times greater than the Gravitational force at the same separation. 


Gravitation has several basic characteristics that distinguish it from the other Fundamental Interactions. First, it is universal, affecting all forms of matter and energy in essentially the same way whereas all the other interactions directly affect only certain types of particles, for example, Electromagnetic force affects only charged particles. Second, Gravitation is always ‘attractive’, since it interacts with mass-energy which is always positive, whereas Electromagnetic forces can either ‘attract’ or ‘repel’. Third, Gravitation is a long range interaction, Electromagnetism is also long-range, but the Strong and Weak Nuclear forces generally operate only within a distance, the size of an atomic nucleus. Fourth, Gravitation is the weakest of the Four Fundamental Forces with negligible effect on elementary particles. 

Sir Issac Newton made the most significant contribution to Gravitational Theory when he perceived (1666) that the orbit of the Moon depended on the same type of force that causes an apple to fall on Earth. According to Albert Einstein’s Theory of Relativity, Gravity affects all forms of matter and energy, all of which move in Space-Time (SPACE-TIME CONTINUUM). 

Gravity is by far the weakest known force in nature and therefore plays no role in determining the internal properties of everyday matter. Gravitational force becomes appreciable only when at least one of the attracting masses is very large, typically of planetary size. A Gravitational force exerted by the Earth on the Moon keeps it in a circular motion about the Earth. The trajectories of planets in the Solar System are determined by the Laws of Gravity. The revolution of the Earth in relationship to the Sun, the motion of the Sun around the center of the Milky Way Galaxy, and the geometric structure of the universe itself are the results of the Gravitational force. Because of its long reach and universality, Gravity plays a central role in shaping the structure of stars, galaxies, and the entire universe. Hence, it would be correct to claim that Gravitational force is the most pervasive and dominant force in the universe. 


It is the force that tends to draw all bodies in the Earth’s sphere toward the center of the Earth. The fall of bodies released from a height to the surface of the Earth and the weight of resting bodies at or near the surface are the most familiar manifestations of Terrestrial Gravitation. 

Because of the Gravitational force exerted by the Earth’s mass, all bodies have a weight or downward force of gravity proportional to their mass. The word ‘GRAVITY’ is derived from the Latin word ‘gravitas’ which means weight or heaviness. 

Atmosphere, the nearly transparent envelope of gases that surrounds the Earth, profoundly influences the environmental, and the climatic conditions on the planet’s surface. Life could not exist without the physical and chemical processes involving the atmospheric gases. Terrestrial Gravitation is the force that holds the atmosphere in its place. 


Human existence upon planet Earth is possible only because of the Four Fundamental Interactions of matter. All living entities are energy dependent. The primary source of energy is Sun. The Strong Nuclear, the Weak Nuclear, and the Electromagnetic force interactions provide the energy that we need for our Earthly existence. According to the Laws of Nature, this source of energy would eventually bring about disastrous consequences to Earthly existence. The Sun continues to spend its abundant hydrogen fuel and the fuel supply is not everlasting. 

The Gravitational force maintains Earthly existence in two ways. Firstly, it maintains Earth’s relationship with Sun and secondly, it firmly holds the Earth’s atmosphere in its place. The most important effect of Gravity is that it provides us our body weights which help us to appreciate the physical reality of our Earthly existence. 


Soil is the earthen material that covers land surfaces and is formed by the action of natural physical, chemical, and biotic forces on the rocks and minerals on the Earth’s surface. Among its many important functions, soil serves as a substratum of plant life. It provides the terrestrial home for land based animals and humans. 

This surface layer of Earth has a characteristic fragrance of its own. It could be described as a sweet smell, a pleasant odor. It is not fruity, flowery, or spicy. The volatile compounds that generate this odor should reach our noses and the gas molecules should get dissolved in the nasal mucus and activate the receptors of s
mell sensation. To perceive this scent, the soil should not be too cold and frigid. At cold temperatures, the odor generating chemicals do not get vaporized. The soil should not be too hot, as excessive heat tends to destroy these scent chemicals. The Earthly fragrance is best appreciated after rain showers and also during the Spring Season. This fragrance is unique and makes planet Earth a special place. This scent is original. In nature, all products such as flowers, fruits, and herbs which are fragrant could be easily identified as the fragrance and its source are connected. The individual components of the soil is not the direct source of earthly fragrance.The physical, chemical, and biotic factors that interact to generate this fragrance are not available on any other celestial body in the universe that we know today.The Four Fundamental Forces are united in their purpose to produce this new and original product. The originality of Earth’s fragrance could be deemed as an act of creation.

Dr. R. Rudra Narasimham,

Kurnool Medical College, Kurnool, A.P., India.,

M.B.B.S., Class of April, 1970.



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