Thanks Sandash,
We are also very constrained by the vastness of space and time relative to our size. In the context of the size of the universe and the time it has been around we have only been searching for life for a very short period of time. The speed that Electromagnetic Radiation (EMR) travels is also very slow compared to the size of the universe.
To put the challenge in perspective, a snail would probably appear to be very fast when related to the size of Australia if compared to the speed of EMR related to the size of the universe (I think that a snail if fit enough travelling at about 0.05 km/h would take about 10 years to travel the straight line distance from Perth to Brisbane). And the time that humans have been around never mind having an ability to detect extraterrestrial EMR signals is tiny compared to the age of the universe.
In short their are immense problems in finding intelligent life via EMR transmissions.
In the shorter term, our best shot at finding some sort of life I suspect is within our own solar system and there are some promising targets, but I doubt that we will find a real "Star Trek" this close by. But hope springs eternal.
