It has been discovered, long time ago, by J.C. Maxwell

[tex]\displaystyle \frac{ds}{dt} = \frac{1}{\sqrt{\epsilon \cdot \mu}}[/tex]

The only thing (which turned out to be the hardest thing to grasp) one needs to realize is that [tex]\epsilon[/tex] and [tex]\mu[/tex] are the fundamental, essential properties of the **space**, that is, of **spacetime**.

The spacetime is essentially the **electromagnetic **phenomenon.

Lengths, time, [tex]\epsilon[/tex] and [tex]\mu[/tex] are its fundamental properties, simply related with the "that's the way it fundamentally is"-law [tex]\displaystyle \frac{ds}{dt} = \frac{1}{\sqrt{\epsilon \cdot \mu}}[/tex].

And, the fundamental, essential relation which connects energy to space is [tex]\Delta E \cdot \Delta t = h[/tex], which follows from [tex]\Delta E = h \cdot \nu[/tex].

That what enables interaction (attaching) of elementary energy and space is their essential **electromagnetic **nature.