Universe is the greatest void in which here and there the fiery balls of stars are floating without any particularly order. So universe has no profundity but vastness only.
Maybe now the Time has come to change this naive point of view on more sophisticated. Does it possible to reveal another civilization in such plane two-dimensional world as we see it today?
In the oceans where there is a depth we have the creatures that live in parallel world but in Universe (two-dimensional world) it's impossible! And that mistake is a main cause of failure in the searchers for. If to admit depth in Universe then one gets many levels for different population, for example, big planets (or small Stars - Saturn, Uranus etc.) are the inhabitants of one stratum and small planets (of Earthly group) are the inhabitants of another, and there are third and fourth levels... Telescope can't see through depth... (only figuratively).