'Undefined Flying Object' or commonly known as 'UFO' is undoubtedly one of the most well-known topic to us. Since the beginning of human civilization, we are amazed on objects or matters, which we cannot define. We take the most active part in discussions related to the undefined matters. The eagerness to define the undefined gets boost through these discussions which include a few facts, some imaginations and some exaggerations for sure.
What is UFO? Theoretically, any flying object which we cannot include among the known flying objects, such as – airplane, rocket, helicopter, kite, bird etc, should be called UFO or 'Unidentified Flying Object'. But what we assume is that any flying object that does not belong to earth or not made on earth, should be called a UFO. We have a notion that a UFO must be an extraterrestrial object.