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This question is inspired by this answer, which cites Gravitoelectromagnetism (GEM) as a valid approximation to the Einstein Field Equations (EFE). The wonted presentation of gravitational waves is …

There is a sort of analog called gravitomagnetism (or gravitoelectromagnetism), but it is not discussed that often because it applies only in a special case. It is an approximation of general relativi …

It's a good observation that the electric and gravitational fields both satisfy Poisson's equation $$ \nabla^2\Phi_G = 4\pi\rho_G, \qquad \nabla^2\Phi_E = -\frac{\rho_E}{\epsilon_0} $$ where $\Phi_ …

I'd like to add mainly to Frederic Brünner's and Anna V's answers. Let's begin with, as Frederic does: Sunlight does not point back to the sun’s true center of gravity, whereas gravity always poi …

Not much sense. Your "center of charge" is nothing but the dipole moment divided by the net total charge. "Normalised dipole moment, if you will". If you take $q|\vec v|$ instead of $q\vec v$, you ge …

It seems to me that means gravitational waves move at the speed of light. And it seems this implies that a similar theory could be drawn up for gravity as Maxwell did for the electric and magnet …

You're right that in general, the right way to think about electromagnetic interactions isn't between charges at all: instead charges each individually act on the field, which intervenes between them. …

Moving mass does generate gravitation different from stationary mass. This is the ''gravitomagnetic'' effect predicted by Lens and Thirring in the 20's and measured by Gravity Probe B: http://en.wik …

If you start with general relativity, and assume small perturbations around a nearly flat metric, it is possible to obtain linearized equations of gravity that look a lot like Maxwell's equations, als …

Why don't we denote presence of matter and energy in space-time (as we do for presence of electric charge) by a 4-vector field? Because energy is not Lorentz-invariant, whereas electric charge is …

In this online tutorial, aimed at pea-brains like me, the authors restate Einstein's equation $$ \mathbf{G}_{\mu\nu} = \frac{8 \pi G}{c^4} \mathbf{T}_{\mu\nu} $$ in words: Given a small ball of …

You have taught yourself through your own experimenting and curiousity a famous lesson. You are indeed doing exactly as Laplace did and your findings are the same as Laplace's. To add to David Hammen …

In electromagnetism, when a charge accelerates, it emits radiation. We know this because we can write the retarded potentials, apply $\vec E=- \nabla V-\frac{\partial \vec{A}}{\partial t}$ and $\vec B …

TL;DR: The factor of $\color{red}{4}$ in the Lorentz force comes morally speaking from trying to mimic a spin-2 field as a spin-1 field. There is no unique/canonical/"correct" normalization convention …

Let's put a more precise description to the other answers, particularly Neil's. First, note that there is a Gauss Law for static gravitational fields, owing to the inverse square nature of the static …