Many acts of physics transpire as fields. A field is a physical quantity represented by a scalar, a vector, or a tensor.
A physical quantity is a mathematical representation of a property in a physical system, which is an arbitrary geometric region under examination. The adjective physical refers to a study of something which may be observed, as contrasted to utterly imaginary concepts.
A scalar is a quantity which is representable as a point on a scale. Scalars are expressed as real numbers.
A vector is a geometric quantity with both magnitude and direction. Vectors are typically represented by arrows. Although a vector has a significance and an orientation, it lacks a position. In physics, a vector is a movement of energy at a certain strength.
A tensor is a geometric object describing linear relations between other geometric entities (scalars, vectors, tensors). Tensors are typically entangled with other tensors, forming a tensor network.
In physics, a field is considered a region of space with integral energy. More pointedly, a field is an energy associated with a spacetime point.
Like energy, fields do not exist. Physics fields are just a mathematical modeling technique: a geometrical way of characterizing phenomenal transformations of matter.
Newton’s law of universal gravitation was an expression of force fields, though Newton lacked the idea of fields. English physicist Michael Faraday coined the term field in 1849, referring to electromagnetism.
Gravity, which is an entropic distortion of spacetime, acts as if it was an attractive force by a body because of its mass. Mathematically, gravity is a monopolar field.
An electrical field has 2 opposite point charges, so is dipolar. The 2 point charges of an electrical field are negative and positive. Electrons carry a negative charge. Protons carry a positive charge. By definition, an electric current flows away from a positive charge and toward the negative charge.
All matter is loaded with electric charges. We are usually unaware of this because the opposing charges within matter – between protons and electrons – neutralize one another.
An electric charge creates a field which exerts an outward-radiating force, called the Coulomb force. The lines of force of an electric field flow between the oppositely charged dipoles.
Charles-Augustin de Coulomb published his speculations on electricity and magnetism in 1785. The Coulomb force came from characterizing static electricity.
The strength of an electric field decreases as the square of the distance from its source. Moving twice the distance from a point charge saps the felt field strength by 1/4th. This inverse-square dynamic is termed Coulomb’s law, though German physicist Franz Aepinus suspected as much in 1759, before Coulomb published his law.
A moving electric charge – an electric current – creates a magnetic field. As everything is always moving, electric and magnetic fields are coincident.
The charges of a magnetic field are like those of an electric field, with the south pole of a magnet analogous to a negative electric charge, and the north pole like a positive electric charge.
The 2 charges in a hydrogen atom, with its single proton (+) and sole electron (–), may be pulled apart to distinguish electric monopoles. That cannot be done with magnets. Magnets are always dipolar. Theorists hypothesize that there may have been magnetic monopoles in the early universe, but none have ever been observed.