Astronomy Cast 3.1: Schrodinger’s Cat (Episode 249)

Schrodinger’s Cat's is an illustration in quantum theory of superposition describing that we can never truly know what is happening to something or what it's doing if we can't see it.  The experiment was done by  Erwin Schrödinger in 1935.  The basic set up of the experiment is a living cat is placed in a steel chamber along with device containing a vial of a very small about of hydrocyanic acid (which is a radioactive substance).  Once the substance starts to decay, it triggers a mechanism that breaks the vial, releasing the acid, which would kill the cat.  Because the container is enclosed and the observer cannot see inside, they are unaware if the substance has started to decay, and if the cat is dead.  Since there is no way of knowing without opening the box, the cat is considered to be dead and alive in what is known as a superposition of states.  It is concluded that because the outcome is determined my the observation, the outcome does not exist unless the observation is made.