Deriving Gravity from Electromagnetism

A "wider issues" post

As I warned (or should that be "threatened"!) in my very first post to this blog, I'll occasionally post something on what I'll call "wider issues". This is the first one, and by comparison with others that I may do in future, it's a fairly small and innocuous one.

Gravity?

So, what is gravity? Everyone will have their own ideas and theories, and I'm no exception. For a long time, I have been attracted to the idea that there is a deep connection, not yet well understood, between gravity and electromagnetism. I'll present an idea below that seems, to me, to make a step forward in this direction.

I am an amateur student of the history of electrical technology. Anyone who delves into this will soon become aware of the shaky foundations of that subject, which persist today.

Early on, I had read Electromagnetic Theory by Alfred O'Rahilly (a must-have book for serious students of this subject), and moved on from that to more recent works by Peter and Neal Graneau, and by Andre Assis. In his paper titled Gravitation as a Fourth Order Electromagnetic Effect, Prof. Assis questions Grassmann's expression for the force between current elements, which is, as he says, the only one which appears in the textbooks nowadays. He implies that we would have done better to use and develop Weber's force law (an opinion I agree with). He points out that:—

"Weber succeeded in unifying electrodynamics and induction with electrostatics with his generalization of Coulomb's force. The next step would then be the unification of these interactions with gravitation. The natural path along Weber's procedure is to generalize even more Coulomb's law in order to derive gravitation. The forces of Ampère and Faraday were derived from second order terms and so the suspicion is that gravitation might be due to fourth order terms."

Prof. Assis then goes on to generalise Weber's Law, and to show that gravitation can indeed be derived from electromagnetism, as an interaction between neutral dipoles. His paper can be found at:—
http://www.ifi.unicamp.br/~assis/gravitation-4th-order-p314-331(1995).pdf

Further reading

For further reading, I'd recommend Prof. Assis' book Relational Mechanics, but with the warning that it probably isn't suitable for some of the more sheeplike followers of Albert Einstein.