"So the rules that we used to govern the motion of a ball or person or car couldn't be used to explain how an electron or atom works."Īt the very heart of quantum theory-which is used to describe how subatomic particles like electrons and protons behave-is the idea of a wave function. "What we discovered in the late 1800s and early 1900s is that really, really tiny things didn't obey Newton's Laws," he says. Schrödinger developed the paradox, says Martell, to illustrate a point in quantum mechanics about the nature of wave particles. Immediately upon looking at the cat, an observer would immediately know if the cat was alive or dead and the "superposition" of the cat-the idea that it was in both states-would collapse into either the knowledge that "the cat is alive" or "the cat is dead," but not both. If, on the other hand, you assume it's in a combination of all of the possible states that it can be, you'll be correct." "If you try to make predictions and you assume you know the status of the cat, you're going to be wrong. "If you put the cat in the box, and if there's no way of saying what the cat is doing, you have to treat it as if it's doing all of the possible things-being living and dead-at the same time," explains Eric Martell, an associate professor of physics and astronomy at Millikin University. In other words, until the box was opened, the cat's state is completely unknown and therefore, the cat is considered to be both alive and dead at the same time until it is observed. (More physics: The Physics of Waterslides.) Until the box is opened, an observer doesn't know whether the cat is alive or dead-because the cat's fate is intrinsically tied to whether or not the atom has decayed and the cat would, as Schrödinger put it, be "living and dead.
Physicists say the atom exists in a state known as a superposition-both decayed and not decayed at the same time. The radioactive decay is a random process, and there is no way to predict when it will happen. When the radioactive substance decays, the Geiger detects it and triggers the hammer to release the poison, which subsequently kills the cat.
The Nobel prize-winning physicist would have turned 126 years old on Monday and to celebrate, Google honored his birth with a cat-themed Doodle, which pays tribute to the paradox Schrödinger proposed in 1935 in the following theoretical experiment.Ī cat is placed in a steel box along with a Geiger counter, a vial of poison, a hammer, and a radioactive substance. His feline paradox thought experiment has become a pop culture staple, but it was Erwin Schrödinger's work in quantum mechanics that cemented his status within the world of physics.