There is nothing in the universe that is more exact than mathematics itself and Dr. Frank Drake decided to take on the challenge. He created a mathematical equation that tells us an estimate of how many alien civilizations are at our level or higher in the Milky Way galaxy. He created this formula called the Drake Equation as a way to stimulate scientific discussion at the worlds first SETI meeting in Green Bank, West Virginia. Great right but lets get down to brass tacks. When the formula is completed it looks like this, N = 7 × 1 × 0.2 × 0.13 × 1 × 0.2 × 109 = 36.4 million (Wiki source). Holy @#$ Batman! That's a whopping number of planets out there that contain civilizations. Yes, because if N=36,000,000 N=the number of civilizations in our galaxy with which communication might be possible.
Of course some of them already know about this, but this raises a new question…why don't they reveal themselves to us? That my friend is easy. Some of these 36,400,000 planets with life have created space faring capabilities…let's say a very low estimate of 1% or 364,000. This number still blows me away, so lets say 1% of 1% has space technology. Thats still 3,640 space faring species!
When humanity is exploring space, usually its funded by governments and you know the red tape and rules they have about the simplest things. Well, aliens have rules about revealing themselves and it probably has serious implications if you are caught breaking their rules. Its a lot like on the TV show Star Trek and how the captain of the USS Enterprise doesn't want to interrupt in other cultures, but circumstance brings it to happen and sometimes it happens by accident. Same thing. They are trying to respect our way of life, and not make us dependent on them and their advancements.
I do believe that if enough messages are received from Earth from not one but may people, aliens civilizations will have to decide that Earth has come a long ways, and perhaps, just perhaps, they will deem humanity ready to meet them. How to send messages? Many ways, but most popular is by radio telescope or laser communicator. I sent hundreds of messages using radio telescopes around the globe, but most of them closed down or stopped allowing messages to be sent. SCW