This is Drake Equation. It is the equation which estimates the number of active extra terrestrial civilizations in our Galaxy. According to Drake equation, there must be tens of thousands of intelligent alien civilizations in our Galaxy. But, if they are so abundant, Why haven’t we met even one? So, today we will look at three reasons, why we haven’t met aliens yet! This point is based on the Great Filter theory. It says that some kind of barrier will eventually stop the rise of advanced beings. It says that advanced beings would have to face their extinction either by natural or technological disaster. The extinction would be unavoidable. It says that any species reaching high level of advancement is bound to disappear sooner or later. Maybe, advanced aliens have evolved so much that the Milky Way may not be enough for them. So, they may have left our Galaxy for newer and better world. According to John Smart’s Trancension hypothesis, all move towards better areas of the universe with their progression. And, progressively, they become more advanced. Black Holes would be the ultimate destination for such beings to escape this Space-Time continuum. Advanced aliens might be watching us from space. Or, they maybe even walking among us. Maybe, they have advanced so much and have developed a cloaking technology that we are unable to detect. Maybe, they are observing us as a curiosity. Or, they maybe observing us as an experiment. So, these were the three reasons why we haven’t been able to make even a single contact. So, this was it for today!