
 Gravitational interaction force between particle and observer (=3D vector) 
 Field vectors to arrive at the interaction force vector 
 Position of particle compared to observer, in direction particle to observer 
 Velocity and acceleration vectors of particle compared to the observer 
 Vector norm of and 
 Velocity of the expansion of gravity in vacuum 
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 Gravitational constant = 6.67 × m^{3} kg^{−1} s^{−2} 
mobs  Gravitational mass of the observer 
mpart  Gravitational mass of the field generating particle 
(, )*  The dot product and cross product 
