Terminal Velocity Revisited

Terminal velocity in a helical path,

Terminal velocity as defined is translation along $c_1$,

Terminal Velocity = $c_1$

Not $c_2$ which is circular speed, changing direction all the time.  Nor it is $c$ the instantaneous resultant of $c_1$ and $c_2$

$c^2=c^2_1+ c^2_2$

Light speed will be $c_1$.  But terminal velocity as a limiting velocity, as a consequent of space density/viscosity then it should be $c$.  That is,

$c^2\propto drag force$

Terminal Velocity = $c$    and
                                         
$c>c_1$

But $c_1$ is the measured value, as such light speed is less than $c$.  By symmetry,

$c_1=c_2$  

because moving in one direction is the same as moving in another in uniform space.

 $c^2=2c^2_1$

$c=\sqrt{2}c_1=\sqrt{2}.light speed$

The actual terminal velocity of space is $\sqrt{2}.light speed$.  This is the velocity by which electrons orbit around the nucleus.  This is also the velocity that prevents the atom from collapsing.

$\cfrac{m_e.2c^2}{r_o}=\cfrac{q^2}{4\pi \varepsilon_o r^2_o}$    and

$r_o=\cfrac{q^2}{8\pi \varepsilon_o{m_ec^2}}<r_{n}$

where $r_{n}$ is the radius of the positive nucleus.

In these expressions, $c^2$ has been replaced with $2c^2$ and in the case for $c$, to be replaced by $\sqrt{2}c$.  The speed limit for charge particles in general is $\sqrt{2}c$.