'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.
Black Hole is I think the most popular mystery in Space Science. The word "black hole" certainly thrills most of us. What is black hole ? Black Hole is a huge mass centered in a very small volume and definitely with very very high density. Generally dead star is the source of the mass forming black hole. Some scientists say that if a star undergoes "Supernova" state and explodes, the scattered mass collapses all together and starts forming black hole. With the time these mass become so dense that it occupies almost zero volume and infinite density.
The Bermuda Triangle, also known as the Devil's Triangle, is a region in the western part of the North Atlantic Ocean in which a number of aircraft and surface vessels are alleged to have mysteriously disappeared and cannot be explained as human error, piracy, equipment failure, or natural disasters. Popular culture has attributed some of these disappearances to the paranormal, a suspension of the laws of physics, or activity by extraterrestrial beings.
Humans are the most intelligent among all the living beings in the world. At least we, the humans think so. From the initiation of our civilization, we have been developing numerous instruments. These instruments were used in daily life and as well as for the servival. We never stoped and kept dveloping the old ones and inventing new ones. With the development of instruments we build devices. And complicated devices formed machines.