The ET search and the hurdles

It is unclear exactly when from a human perspective we became interested in life outside the wall of our atmosphere, but it has become a large feature and interest in today's scientific community. It is thought that ancient art depicted aliens visiting earth. There is no denying that some of the images raise valid questions in terms of alien visitation.

We have been searching for signals and proof of alien life for decades now. With SETI (Search for Extra Terrestrial Intelligence) we have a global network of astronomers and amateur astronomers looking and listening. Giant telescopes peer into the wonders beyond our worlds, looking at planets, at stars, at moons for habitable worlds, they are alsosearching for 'artificial' radio waves or any signal broadcast from another civilization.

Let's put a bit of perspective into this though. Our nearest star of note is Alpha Centauri. Just around the corner in cosmic terms at a mere 25,8 Trillions miles away. (or 41,52 Million Kilometers.). Assuming we could travel the speed of light, or at least very close, this journey would take us between 4-5 years to complete. As yet, the laws of physics have proved we cannot travel the speed of light. We probable will not come close. So this journey becomes so much longer should we ever decide to venture to this neighbour.

In my opinion, there are problems in our search limitations. Let's speculate that somewhere, other beings are doing the same. By some miracle a signal is sent in our direction and reaches earth. Firstly, we have to hope we have technology that could recognize it. For argument sake, let's say we do. Although radio waves travel at the speed of light, they would have to cross vast distances. Should we detect and recognize it as an artificial message, we would have to hope for more so we can verify it. Secondly, we have to hope it is something we can understand. (Symbolic or mathematical etc). Once this is achieved, we have proof of life. But this will not be enough. We would have to send a message back, and hope that they receive and understand it. It would hardly be a flowing conversation considering that it would take double the time to receive a reply. (5 light years there and 5 for our reply- assuming it is so close). So this may not be a very promising way of establishing. I am not saying it is useless, just far from an ideal solution.

So far scientists have found a number of earth like planets. We base our search for life in terms of our carbon based platform. With this in mind, we seek solar systems that have planets that could accommodate life as it is on earth. This to me is short sighted. Life on earth, may be different to other life. There may be beings who breath methane, who look upon the Earth and declare nothing could live among all the oxygen and water. There may be beings who do not need to breath at all. Any 'life; would obviously adapt to it's environment to ensure it's survival. Even on earth we have bacteria that do not need oxygen, bacteria that live in hot vents or in extreme cold conditions. And this is on Earth.  The universe is immense and although I am sure there is more than one planet or body with a certain type of life on it, I am highly doubtful it is close to earth like. Our parameters need to be expanded. 

At the moment space travel to distant worlds is close to impossible, unless we learn techniques to create and use wormholes etc.

This is just a brief thought on the subject. To elaborate would take way more than people may want to read.
If life is simple cell like critters they may come to us on comets and asteroids- they may have already landed on earth and perished due to our world not being favourable to their survival. Or an advanced species may find us (if they have not already). But as for our search, I am not holding my breath.