Erwin Schrodinger, a scientist famous for several scientific laws and the infamous thought experiment, subsequently refered to by many people since as ‘Schrodinger’s Cat’, to reference a certain idea…..
The idea is this: Something, if unobserved, could BE in two states at the same time, until observed….. with the cat, it could be both dead and alive, at the same time.
Here’s the gist of the Schrodinger’s cat thought experiment:
A cat is placed into a box with a little bomb, that may, or may not (50/50 chance) explode and so may or may not (50/50 chance) kill the cat.
With both placed inside and the lid closed, there is no way of knowing if the little bomb had gone off, so have no way of knowing if the cat is/was, at any one moment, dead or alive.
With this scenario, Schrodinger worked a theory, that it, the cat, (whilst un-observed inside the box) could be BOTH dead and alive at the same time….. Up until the time the box was opened and the cat observed….. At the point of observation, the cat would reveal itself (and become) either dead or alive….. one state or the other….. but not both.
– Just for your info:
Schrodinger only did this as a thought experiment (no cat was actually subjected, with bomb, to a box)….
The key points:
1. Before observation, the cat is in both states, simultaneously….. Today called “superposition”.
2. Only when observed, does the cat become either dead or alive….. Today considered a “collapsed wave function“.
Thought experiment to real-world realisation:
A cat is a complex “object”… but is a known object that most can picture… so to use it in a thought experiment works well.
The point of the thought experiment actually, today has been found to exist at the quantum level.
Todays scientists have discovered that somewhat less complex “objects” such as photons… can be entangled with another photon.
… Once entangled… these two entangled photons were separated (unobserved)… one was left at home, the second was taken away to a place, some distance away.
Now this…
When the home one was observed for the first time…. It collapsed from superposition.
Now Now this…
At the same time (instantaneously):
The second one, elsewhere… collapsed from superposition.
Einstein called this observational discovery… “Spooky action at a distance“.
One use of this today… The Pony Express… “Secure“
The original pony express, used horses to gallop the post across distance… as fast as fast could be… horses… fresh horse relays etc etc. The horse was the fastest thing they knew at the time.
Today we use tech methods to send messages at or near the speed of light across distances…. the entangled feature allows for a secure cross check that the message has not been intercepted or tampered with on route… if it was, at any point, it would be instantaneously revealed.