The thought experiment often reffered to as "Schrödinger's Cat" was devised by Austrian physicist Erwin Schrödinger in 1935. Theoretically, a cat is placed in a sealed box along with a flask of poison, a radioactive source and a geiger counter. If the geiger counter detects radioactive decay in a given time such as one hour, a hammer will be released breaking open the container of poison and killing the cat. There is also an equal probability that no radioactive decay will occur and the cat will live. According to Quantum Theory, the cat may be both alive and dead until somebody opens the box and makes an observation.