Then you know that the medium is vacuum in free space.


And by the way, it's "epsilon naught", not "epsilon not".
"Naught" means "zero", and "epsilon naught" means " ε0 " .

V

There is no star with that name. Many stars have names that start with "Epsilon", followed by the genitive of a constellation, e.g. "Epsilon Cruxis", "Epsilon Geminorum", etc.

If its epsilon segin cassiopeia, it is 520L/Y(light years) away from earth.

Epsilon Minus was created in 2000.

Lancia Epsilon was created in 1911.