
Life, as it is the most beautiful creation of the universe. If we compress the life of the universe to a year worth of time period, life on earth would constitue an hour.This is how short our stay in the universe has been. And considering this fact, it is very possible that there could be civilizations out there who have been flourishing millions of years before us and would have had the capability to civilize the whole galaxy by now.But the fact that we have not found them,rather they have not found us yet makes me doubt their existence.
Firstly,it is very possible that life might exist on other planets but it might no be intelligent life that can communicate.On the other hand, it is also very possible that intelligent life capable of communicating exists but with hundreds of billions of stars to look into, they have not been able to reach us.I fail to believe on the concept that they have been visiting us but have been hiding.I fail to understand that a highly advanced civilization has been in contact with our planet,has been observing us but is hiding and doing it all. For such an advanced civilization that can reach us, with immense knowledge and intelligence , I would not expect them to be foolish or come with a bad motive when they there are millions of other planets. No one would want to conquer anything when plenty turns out of be to small a world to explain the vastness of the universe.
I believe there are hundreds of civilizations out there who just have not made it. But someday they will contact us, they will find us.The Earth is just one of millions of other planets which can support life and we are not that special to be the only carriers of intelligence and life in this extreme vastness of space.For that to happen we should have been granted much more intelligence to sustain ourselves for we are so special and not destroy our planet at the rate we are doing right now.
To sum it all up,I strongly believe there have to be many civilizations out there who just have not reached us, but someday they might just pop up!!