The definition of electric force `F_e` between 2 charges `q1` and `q2` is

`F_e =(1/(4*pi*epsilon0))*((q1*q2)/R^2)`

Also the definition of gravitational force `F` between 2 masses `m1` and `m2` is

`F = G*(m1*m2)/R^2`

Remember that because basically the surface of a sphere is `S=4*pi*R^2` , the General Theory of Relativity states that any mass `m` is warping (curving) the space around, the constant `G` showing how much this curvature of the space is.

Now, because the two laws are similar, it has been suggested that in the
same manner, an electrical charge `q` is warping the space around it,
**the value of the constant `1/epsilon` showing how much this curvature
of the space around it is in a certain medium.**

This is the Kaluza-Klein theory, which tries to unify the gravitational field with the electromagnetic field.

Until now, only the electric and magnetic field have been unified (in other words it has been shown that they are different faces of the same field), and named the electromagnetic field. Unfortunately the Kaluza-Klein theory (which was published only about 10 years after the General Theory of Relativity- GTR) did not succeed in its efforts. This theory predicted 5 dimensions of the space (instead of 4 in GTR) and starting from it, during the last 40 years, or so, the string (and super-string) theory has been born. The string theory, predicts more than 5 dimensions of the space and give today physicists big promises to unify all fields known in nature into a single field. This is what is called the Unified Field Theory, the Holy Grail of the modern physics.

**What is absolute permittivity of free space?**

It is the well known constant, called as dielectric constant. It is the permittivity in a vacuum.

It is equal to 8.854187817620 x 10^(-12) Fards per meter (Fm^(-1))

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**Further Reading**