Schrödinger's Cat is a famous thought experiment in quantum mechanics. Imagine placing a cat inside a sealed, non-transparent box along with a vial of poisonous gas and a radioactive substance. The radioactive material has a chance to decay randomly. If it doesn't decay, the cat survives; however, if it decays, a mechanism is triggered, releasing the poisonous gas and causing the cat to die.

In this closed system, the fate of the cat is closely tied to the radioactive substance. According to quantum mechanics, at a certain point in the experiment, without opening the box, the cat exists in a "superposition" state—both alive and dead at the same time, with each possibility having an equal probability. When the box is opened, and we "measure" the system, the quantum state of the cat "collapses" into a "definite state"—the cat becomes either alive or dead, but not both.

The Glove Thought Experiment: Imagine a pair of gloves (one left-hand and one right-hand) being "entangled" and placed in two separate sealed boxes. Before opening the boxes, we don't know which glove is in which box. According to the principle of superposition in quantum mechanics, before any "measurement" is made, the system remains uncollapsed into a "definite state," and thus there is an equal probability of finding either glove in each box. Now, suppose these boxes are sent to two distant locations—so far apart that they are beyond the reach of light within the time it takes to open the boxes. If we open one box and find a left-hand glove, we instantly know the other box contains the right-hand glove.

This seems to contradict the concept of "quantum collapse" because no measurement was made on the second box. However, once we measure one box, we instantly know the state of the glove in the other box, as if information traveled faster than light, defying special relativity. This is what Einstein famously referred to as "spooky action at a distance," where quantum entanglement allows for instant correlations across vast distances.

However, this doesn't mean that quantum entanglement can be used to transmit usable information. Regardless of how we measure one box, the probability of finding either glove in the other box remains equal, and the observer at the second box will not know whether a measurement has already been made on the first box. Therefore, quantum entanglement does not violate special relativity.