Maybe, Contact Is Impossible...
OK, since the Universe is endless, the probability of existence of self-regulating forms of material existence on the other planets differs from zero. Self-regulation may stay in borders of unintelligent homeostasis (like in any primitive animal), but it can lead to some forms of intelligence.
But there may be millions of reasons of absence of contact with these forms of life:
1. Their information transfer media may be very different from ours (for example, we perceive electromagnetic waves in wavelengths range 350-700 nm as a visible light; if the visible light of "aliens" is, for example, in range 150-1,000 m, then we should be merely invisible for them, being in their perception absolutely transparent). Besides this,
they may use other physical phenomena for information transfer (for example, electric charge of the ionized atoms, or polarization parameters of electromagnetic radiation), and these are meaningless for us, just as our ways are meaningless for them. From another side, they may have semantic principles that have nothing in common with ours, this making any translation from "Alienish" into English an impossible mission (all the human languages have more or less similar principles of semantics, differing from each other by vocabulary, grammar, alphabet, etc.).
2.
They may be located so far from us that a simple dialogue like "How are you? OK, thank you" may take several million years. Let us put aside all the curvatures of space being exploited by science fiction authors; creation and usage of "wormhole" may require more energy can be obtained from all the energy rich natural resources of the Earth (including deuterium of water as a possible fuel for some thermonuclear machines/bombs).
Besides this, the outer space civilization
may be quite self-sufficient and not interested in any contacts with anyone.
3.
The "aliens" may be on the development stage that does not enable them even to perform orbital flights, put aside trans-galactic ones (the same refers to their telecommunication abilities). Maybe, space exploration is not on their list of priorities, neither is development of telephony/radio/lasers.
These are only few of the reasons making me very skeptical toward all these stories about flying saucers, jet propulsion mugs and supersonic cutlery
. But, from other side, there are no reasons to deny possibility of the aliens' existence.
Fundamental physical laws are the same anywhere in the universe, and if our existence is possible under these conditions, theirs may be possible as well.