Daisy Dai
Grade11 Class1
Physics

Whether the Gravity is the product of the Electromagnetism I. Introduction Gravity and electromagnetism are both the fundamental forces in the world; they are unique in physics and thought of some connections between them by some scientists. However, according to the studies, gravity isn’t a product of electromagnetism because they are juxtaposed to each other in physics’ identifications. From the formula (G=mg) created by Newton, the gravity is related only to mass. And this leads concept of gravitational fields. But the electromagnetic force are definitely different from that one. It is related not to mass but to the electric charge（F=qvB), and this leads to the concept of electric field. Since the Earth exists the gravitational field, the electric field and the magnetic field which don’t have any affiliation with each other by observing the formulas, they will not have connection with each other. But for electric and magnetic force, the sources of magnetic fields are electrical currents, caused by moving electric charges or small dipoles associated with molecular and atomic structure. So, there is electromagnetic force that electromagnetism exists in the universe. However, these forces actually have connections with each other instead of non-connection relationship. In fact, gravity is not the subordinate relationship with electromagnetism but the similar ones. All magnetic forces on matter are also proportional to the electric charge on that matter, but also depend on the velocity of the matter. Hence, like electric forces, they are not proportional to the mass. Hence, any attribution of gravitation to electromagnetism is not possible in the current paradigms of physics. This article seeks the question that whether the gravity is the product of electromagnetism. And as far as I concern, this isn’t true that gravity is the product of electromagnetism. To verify the statement, this paper’s body is divided as three parts: the cause and effect of gravity, the cause and effect of electromagnetism, the similarities and differences between gravity and electromagnetism and the connection between them. Finally, there is a conclusion about general context at the end of the paper. II. Body 1. the Concept and Effect of Gravity Gravity (or gravitation) is a natural phenomenon by which all things with mass are brought towards one another. It is responsible for the complexity in the universe, by creating spheres of hydrogen — where hydrogen fuses under pressure to form stars — and grouping them into galaxies. Without gravity, the universe would be an uncomplicated one, existing without thermal energy and composed only of equally spaced particles. On Earth, gravity gives weight to physical objects and causes the tides. In different theories, there are different definitions about gravity — Newton’s law defines gravity as a force, but in general relativity, it’s a consequence of the curvature of spacetime caused by the uneven distribution of mass/energy that results in time dilation, where time lapses more slowly in strong gravitation .In general relativity, the effects of gravitation are ascribed to spacetime curvature,which relates to the field equations Einstein discovered. Albert Einstein knew that gravitational radiation could not propagate at a speed faster than the speed of light. And if it propagated at the speed of light, gravity (like sunlight) would not point back to the sun's true location; and as a result the planets would drift away from the sun and leave the solar system. So he said that gravity could not be a force. And because he knew that the gravity of a massive body (star) could act as a "gravity lens", and that it was the curvature of a lens that focused light; he proposed that gravity was the curvature of 4-dimensional space-time around a body, and developed the mathematics to describe it. However, according to Newton’s law of universal gravitation, the equation (F=GMm/r²）illustrates that gravity is a kind of force. Although Newton's theory has been superseded by the Einstein's general relativity, most modern non-relativistic gravitational calculations are still made using the Newton's theory because it is simpler to work with and it gives sufficiently accurate results for most applications involving sufficiently small masses, speeds and energies. People believes that gravity causes objects fall. The equivalence principle, explored by a succession of researchers including Galileo, Loránd Eötvös, and Einstein, expresses the idea that all objects fall in the same way. The simplest way to test the weak equivalence principle is to drop two objects of different masses or compositions in a vacuum and see whether they hit the ground at the same time. Such experiments demonstrate that all objects fall at the same rate when other forces (such as air resistance and electromagnetic effects) are negligible. More sophisticated tests use a torsion balance of a type invented by Eötvös. Satellite experiments, for example STEP, are planned for more accurate experiments in space. Formulations of the equivalence principle include: the weak equivalence principle; the trajectory of a point mass in a gravitational field depends only on its initial position and velocity, and is independent of its composition; the Einsteinian equivalence principle; the outcome of any local non-gravitational experiment in a freely falling laboratory is independent of the velocity of the laboratory and its location in spacetime. And the strong equivalence principle requiring both of the above. The force of gravity on Earth is the resultant (vector sum) of two forces: (a) The gravitational attraction in accordance with Newton's universal law of gravitation, and (b) the centrifugal force, which results from the choice of an earthbound, rotating frame of reference. This is also very different from electromagnetism.

2. the Concept and Effect of Electromagnetism Electromagnetism is a type of physical interaction that occurs between electrically charged particles, the force that acts between electrical charged particles and includes both electricity and magnetism as elements of one phenomenon, and the combined effect of electric and magnetic forces acting between charged particles moving relative to each other. It governs the interactions between the electrons of neighboring atoms, which are in turn determined by the interaction between electromagnetic force and the momentum of the electrons. All electromagnetic phenomena are underpinned by quantum mechanics, specifically by quantum electrodynamics (which includes classical electrodynamics as a limiting case) and this accounts for almost all physical phenomena observable to the unaided human senses, including light and other electromagnetic radiation, all of chemistry, most of mechanics( excepting gravitation), and magnetism and electricity. The electromagnetic force is the one responsible for practically all the phenomena one encounters in daily life above the nuclear scale, with the exception of gravity. Roughly speaking, all the forces involved in interactions between atoms can be explained by the electromagnetic force acting on the electrically charged atomic nuclei and electrons inside and around the atoms, together with how these particles carry momentum by their movement. Electromagnetic force is one of the four fundamental interactions in nature, which the other three fundamental interactions are the strong interaction, the weak interaction, and gravitation. Between these forces, there is a unified description of electromagnetism and the weak interaction — electroweak interaction. Although these two forces appear very different at everyday low energies, the theory models them as two different aspects of the same force. Above the unification energy, on the order of 100 GeV, they would merge into a single electroweak force. Thus if the universe is hot enough (approximately 1015 K, a temperature exceeded until shortly after the Big Bang) then the electromagnetic force and weak force merge into a combined electroweak force. During the electroweak epoch, the electroweak force separated from the strong force. During the quark epoch, the electroweak force split into the electromagnetic and weak force. 3. Similarities and Differences between Gravity and Electromagnetism 3.1 Similarities One of the several analogies between weak- field gravity and electromagnetism is that , analogous to electromagnetic waves, there are gravitational waves: ripples in the metric of spacetime that propagate at the speed of light. The simplest type of such a wave can be visualizedElectromagnetic Wave
Electromagnetic Wave by its action on a ring of freely floating particles. A sine wave propagating through such a ring towards the reader distorts the ring in a characteristic, rhythmic fashion (animated image to theGravitational Wave
Gravitational Wave right). Since Einstein's equations are non-linear, arbitrarily strong gravitational waves do not obey linear superposition, making their description difficult. However, for weak fields, a linear approximation can be made. Such linearized gravitational waves are sufficiently accurate to describe the exceedingly weak waves that are expected to arrive here on Earth from far-off cosmic events. Not only gravitational and electromagnetic forces propagate at the speed of light but also the fields. Changes in gravity and electromagnetic fields propagate at the speed of light. Despite thought experiments to the contrary, you can't instantaneously change either. Everything, matter/energy and electric charges, moves at the speed of light (energy only) or less and the subsequent changes move out at the speed of light. The field lines are already there. Also, by looking at their equations, both forces scale as 1/r^2, where r is the distance between the two massive objects (in the case of gravity) or the two charged objects (in the case of electromagnetism). In addition to the forces between two sources (mass m and M or electric charge q and Q) being inversely proportional to the square of the distance between the two sources (F ~ Mm/r^2 and f ~ Qq/r^2), both set up force fields. For gravity, we have a gravity force field; for EM, we have the electric and magnetic force fields. According to Einstein's General Relativity, a curvature or displacement in a "surface" of a three-dimensional space manifold with respect to a fourth “spatial” dimension; because mass is a form of energy it should, according to the concepts contained in that article cause a displacement in space and objects interacting with it will experience a differential force directed towards the apex of the curvature caused by that displacement. This force is called gravity. a matter wave on the "surface" of a three-dimensional space manifold with respect to a fourth “spatial” dimension would cause a point on that "surface" to become displaced or rise above and below the equilibrium point that existed before the wave was present. Therefore, classical wave mechanics, if extrapolated to four “spatial” dimensions tells us a force will be developed by the differential displacements caused by a matter wave moving on a "surface" of three-dimensional space with respect to a fourth “spatial” dimension that will result in its elevated and depressed portions moving towards or become "attracted" to each other. This defines the causality of the attractive forces of unlike charges associated with the electromagnetic wave component of a photon in terms of a force developed by a differential displacement of a point on a "surface" of a three-dimensional space manifold with respect to a fourth “spatial” dimension. However, it also provides a classical mechanism for understanding why similar charges repel each other because observations of water show that there is a direct relationship between the magnitudes of a displacement in its surface to the magnitude of the force resisting that displacement. Similarly the magnitude of a displacement in a "surface" of a three-dimensional space manifold with respect to a fourth “spatial” dimension caused by two similar charges will be greater than that caused by a single one. Therefore, similar charges will repel each other because the magnitude of the force resisting the displacement will be greater for two charges than it would be for a single charge. One can define the causality of electrical component of electromagnetic radiation in terms of the energy associated with its "peaks" and "troughs" that is directed perpendicular to its velocity vector while its magnetic component would be associated with the horizontal force developed by that perpendicular displacement. However, Classical Mechanics tells us a horizontal force will be developed by that perpendicular or vertical displacement which will always be 90 degrees out of phase with it. This force is called magnetism. This is analogous to how the vertical force pushing up of on mountain also generates a horizontal force, which pulls matter horizontally towards the apex of that displacement. There are actually other similarities between gravity and electromagnetism. First, they are both passive. They won’t be propagated by themselves. Second, they both vary from place to place. The gravity changes in different altitudes, and the electromagnetism changes with distances the objects move. Then, Both are Vector fields and both fields are force fields. Also, both fields exert force with a speed equal to the speed of light. In December 2012, a research team in China announced that it had produced measurements of the phase lag of Earth tides during full and new moons which seem to prove that the speed of gravity is equal to the speed of light. And the speed of light is the speed at which all massless particles and changes of the associated fields (including electromagnetic radiation such as light and gravitational waves) travel in vacuum. In addition, by looking at the force equations of gravitational force (F = GMm/R²) and electrostatic force (F = keqQ/r²), the similarities and how gravitational force can be considered parallel to the force between two charges. Besides being proportional to the inverse of the square of the separation, both forces extend to infinity and travel at the speed of light. 2. Differences There are many differences between gravity and electromagnetism that can emphasize the statement that they are not in subordinate relationship. First of all, radiation. Both gravitational and electromagnetic radiation exist in the universe, but they are very different from each other. Firstly, gravity is a weak force, but has only one sign of charge; electromagnetism is much stronger, but comes in two opposing signs of charge. This is important because it shows why these two phenomena so differently that have following consequences: (a) significant gravitational fields are generated by accumulating bulk concentrations of matter; electromagnetic fields are generated by slight imbalances caused by small (often microscopic) separations of charge. (b) Gravitational waves, similarly, are generated by the bulk motion of large masses, and will have wavelengths much longer than the objects themselves; electromagnetic waves, meanwhile, are typically generated by small movements of charge pairs within objects, and have wavelengths much smaller than the objects themselves. (c) Gravitational waves are weakly interacting, making them extraordinarily difficult to detect, and at the same time, they can travel unhindered through intervening matter of any density or composition; electromagnetic waves are strongly interacting with normal matter, making them easy to detect; but they are readily absorbed or scattered by intervening matter. (d) Gravitational waves give holistic, sound-like information about the overall motions and vibrations of objects; electromagnetic waves give images representing the aggregate properties of microscopic charges at the surfaces of objects. Secondly, gravity is a weak force, but has only one sign of charge (positive); electromagnetism is much stronger, but comes in two opposing signs of charge (negative and positive). Although electromagnetism and gravity produce significant forces at macroscopic scales where the effects can be seen directly in every day life, they still have some difference by observing the fundamental interactions. Gravity is the weakest of four interactions and the only force that can act on all particles having mass, energy and/or momentum. But for electromagnetism, the force that acts between electrically charged particles, a phenomenon includes the electrostatic force acting between charged particles at rest, and the combined effect of electric and magnetic forces acting between charged particles moving relative to each other, it’s far stronger than gravitation, electrostatic attraction is not relevant for large celestial bodies, such as planets, stars, and galaxies, simply because such bodies contain equal numbers of protons and electrons and so have a net electric charge of zero. Nothing "cancels" gravity, since it is only attractive, unlike electric forces which can be attractive or repulsive. Also, gravitation cannot be absorbed, transformed, or shielded against. In the contrary, it’s possible to shield spaces from electromagnetic force. What’s more, they have many differences in the fields as well. The behavior of the electromagnetic field can be resolved into four different parts of a loop: (1) the electric and magnetic fields are generated by electric charges, (2) the electric and magnetic fields interact only with each other, (3) the electric and magnetic fields produce forces on electric charges, (4) the electric charges move in space. But for gravitational field, it’s not the same. In physics, a gravitational field is a model used to explain the influence that a massive body extends into the space around itself, producing a force on another massive body. Thus, a gravitational field is used to explain gravitational phenomena, and is measured in newtons per kilogram (N/kg). Also, the difference between can apparently find through looking at their unit. If gravity is the product of electromagnetism, their unit should be the same or similar one. But in fact, they are not one. And this is seen in the following application.

| Electrostatic force | Gravitational force | Appropriate law | Coulombs law | Newton's law of universal gravitation | Appropriate equation | : | | Labels | • Fe is the electric force between the charges • Ke is Coulomb's constant • q1 is the first charge • q2 is the second charge • r is the distance between the centers of the masses. | • Fge is the gravitational force between the masses, • G is the gravitational constant • m1 is the first mass • m2 is the second mass • r is the distance between the centers of the masses. | Values | • Ke = 8.988 × 109 N m2 C-2 • qelectron = -1.602×10−19C • qproton = 1.602×10−19C • r = 1m (arbitrary) | • G = 6.674 × 10-11 m3 kg-1 s-2 • melectron = 9.109×10−31 kg • mproton = 1.673×10−27 kg • r = 1m (arbitrary) | Units | • N = Newtons • m = meters • C = Coulombs | • m = meters • kg = kilograms • s = seconds |

The other difference is that Gravity affects all objects no matter what their compositions and properties are. Even plastics and wood can be affected by the force of gravity. On the other hand, magnetism only affects specific objects. Some objects are insensitive to magnetism while others are highly sensitive to the force of magnetism. Since magnetism is the sub element of electromagnetism, it’ll be suitable for electromagnetism as well. 3. Connection between Electromagnetism and Gravity Although there has been continuous serious investigation into the possibility that gravity and electromagnetic forces are linked, there is still no certification about this connection, not even mention whether gravity is the product of electromagnetism. Unified theories of forces have been continuously interested to physicists. Some of the more famous examples include Maxwell in 1855 who showed electric and magnetic lines of force could be described by a single set of equations; Einstein died working on a unified field theory to explain the relationship between gravitation and electromagnetism and more recently, the 1999 Nobel Prize was awarded for work toward deriving a unified framework for all the theoretical forces (Hooft).

III. Conclusion It is apparently difficult to integrate gravity with electromagnetism or any fundamental forces of nature. Although they have some similarities, or even the same characteristics, it’s still hard to say that they are in a subordinate relationship. There are many differences between them which can differentiate them so widely that make it hard to say one is the other’s product. For so many evidences shown in the paper, it’s convincing to verify the statement that electromagnetism and gravity aren’t affiliations. Both of them are fundamental interactions of nature in the universe that they are everywhere in daily life. So, it’s rational that gravity and electromagnetism are in the position that are juxtaposed to each other instead of the subordinate relationship. IV. Reference 1. Douglas M. Snyder, “A Connection between Gravity and Electromagnetism”
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