Vacuum permeability - Aetherwisp

The vacuum permeability or permeability of free space $\mu_{0}$ is a dimensional constant that binds the magnetic phenomena to mechanical quantities like force through electric current. In SI units it is

\mu_{0}=4\pi \times 10^{-7}\ \frac{\text{N}}{\text{A}^{2}}

This value used to be empirically determined, but the value was so close to exactly the one above that during a reform it was arbitrarily set to the exact value above, instead allowing the value of the Vacuum permittivity vary to satisfy their connection to the Speed of light:

c=\frac{1}{\sqrt{ \varepsilon_{0}\mu_{0} }}