# Links Between Electromagnetic, Electro Static and Gravitational Fields?

When Studying the properties of matter, I came across the properties of Gravity, electromagnetism and electro static fields I'm Wondering:

As Gravity and Magnetic Fields a alike and some formulas for finding out the gravity are the same could the three have the same properties. (I have not metioned much of electro static forces as I am not fully knowledgeable in that area of science).

Please can someone clear up this matter

## Answers and Replies

At first glance you're right because, classically, the Gravitational Field obeys the same Poisson's equation as Electrostatic Field do, namely
$$\nabla^2 \phi = - c \rho$$
with $$\phi$$ electrostatic or gravitational potential and $$\rho$$ charge or mass density and c an appropriate constant.

But this view is quite naive...because we know since Maxwell that there exist a unique entity called Electromagnetic Field which is governed by 4 equation which have nothing in common with gravity, once you plug in the time dependence. Remember also that the electromagnetic field you measure depends on your state of motion, this is hardly wrong for gravity!!!

Ciao!!

Yet If The Gravitational field is recorded it shows similar constraints as a magnetic field...
Does It Not?

Photos showing similarity between magnetic field (left) & electric field (right), indicating they obey the same rules. Same force fields apply to gravitational fields between 2 masses.
Please View The Two Picture attatchments.

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Yes, it's true. But I think that a quite remarkable feature of physics is that you can apply a common mathematical structure (such as the "technology" of field line you quoted) to the most different topic or physical situation. From this point of view the fact that the field line of a system with two masses or that of a magnet or that of a couple of charges are similar is nothing more than an accident...

If your idea is to find analogies between the gravitational field and electromagnetic field I think that you're going to change your mind when you will study General Relativity because that is the correct (unless untill now...) framework to deal with gravitation.

Ciao!!

Diverting from my initial question, We both know black holes have gravity-
but isn't the gravity another method of a curve in the space-time continuum. Therefore, because we know that a black holes gravity pulls everything - even light wouldn't the light (according to Planck's formula) be gaining speed as it travels?
If this is true (however unprovable it may seem) wouldn't the light travel into it's own past light cone. (If you believe that if you travel quicker than light you shall go back in time).

Unfortunately the relativity forbids the speed of light to be changed...what happens is that the energy of the photon falling in a gravitational field grows up, so does his frequency ( E = h f ) and what you observe is a sort of gravitational red shift...experimentally observed! So the theory accounts for the fact that the light change its motion, but not its speed.
A thing that always amaze me is the opposite of this...I mean...if matter/energy can, actually do, curve the spacetime it would be in principle possible to create a wave packet of light so energetic to be able to modify the gravitational fields of the solar system for instance and in some figurative sense you can "stop the moon by turning the light on"!!!!

what about if the relativity was changed so light is the operandum. therefore being able to change the C Value.