In a previous blog post entitled "Electro-magnetic origin of the inertial mass", it was shown that by affirming a radius of the electron(proton) a reinterpretation of the calculations of Mario Rabinowitz could account for the existence of the inertial mass of matter. It then naturally begs the question, if electromagnetism is indeed the cause of the inertial mass, could it be that it is also the cause of the heavy mass of matter, or put in other words, the very cause of what we call gravitational attraction. There are some intuitive reasons for assuming this:
1. Gravity and Electromagnetism both follow the inverse square law
2. Ordinary electrostatic attraction is 10^36 times greater than gravitational attraction, hence a minuscule net dislocation of charges of celestial bodies could account for gravity.
3. Having only one force is more economic
It turns out that this idea has already been elaborated on in detail. Please check out the following paper:
Deriving gravitation from electromagnetism
Can. J. Phys. 70, 330-340 (1992)