The Doomsday Clock is a symbolic clock face that represents a countdown to possible global catastrophe. It has been maintained since 1947 by the members of The Bulletin of the Atomic Scientists' Science and Security Board.The closer they set the Clock to midnight, the more vulnerable the scientists believe the world is to global disaster.
Yes, the Doomsday Clock exists, whether or not you agree with it. There are people who analyze the world and try to decide when the end of the world is going to be. They might not be right, but they are doing it just for fun and for a warning. People can choose whether to agree with it.
There is not a real doomsday clock. Yes, someone claims to have calculated a time on his doomsday clock, however, there is no real way to quantify the end of the world. Much of the this talk is over-hyped anyways. No one knows when, if, or how the world will end.
In our minds the Doomsday clock might exist, but in reality there is no such clock. The Doomsday clock is the theoretical clock that counts down to a world catastrophe. Countless time people have suggested the end of the world is at hand. We are still here. For those who keep this clock in their mind, the clock has run out at one time or another. Not a very accurate clock at that.