when is Schroedinger's cat dead, and when is it not?

Clearly a feral cat.

The thought experiment is intended to illustrate the Copenhagen Interpretation of quantum mechanics, which states that a system can exist in a superposition of different states, each of which has only a certain probability of being observed. Only when you go to observe which state it is in, does it assume one of them, in this case, alive or dead. Normally, this effect is negligible for macroscopic objects, but this thought experiment is designed to make a macroscopic object depend on a something very small, the radioactive decay of individual atoms. The Copenhagen Interpretation is in contrast to the Many Worlds Interpretation, which speculates the universe branches into multiple alternate universes in which each possible outcome occurs. Actually, with the Many Worlds Interpretation, you'd observe the same thing, but the explanation would be different.

BTW, moving on to science fiction, there is an interesting recent, low budget movie about these concepts called "Coherence."

Schrödinger's cat has been inside the box since 1935 WITHOUT food and water. Though we can't determine the date of death now, it's likely it died 79 years ago.

Let's get over this thing and just simply leave the box shut forever more.

Always !

It's modern mythology.......................As real as constellations of animals.

So, now you're directly contradicting the world physics community. If you don't withdraw from this conversation, I will immediately give you a high school physics problem to see how you do with it. No one who can't do high school physics should presume to tell the world's physicists that they're wrong.

The high school kid rambles.........

Nope, that is a 2 dimensional image of an oscillating cube, that has no mass, thus contains no cat.

So if Schrodinger's cat purrs in the woods and nobody hears it, it didn't make a sound.

Thanks for clearing that up.

Alright, since you presume to tell the world's physicists that they're wrong, let's see if you can operate in physics at even the high school level. Here is a problem such as students in their first physics class would be expected to be able to solve:

A bullet of mass 10 grams srikes a simple pendulum of mass 2 kg and remains embedded in it. The center of mass of the pendulum rises a vertical distance of 12 cm. Calculate the bullet's initial speed.

The minute that you wimp out, I'll write the complete solution.

The lack of wisdom, that is commonly called youth (13-17), often believes that it can make irrational demands upon society. So do feel free to use the question that your high school algebra teacher postulated to you, for the purpose of amazing yourself. This topic is old and dead, but comes back to life with each new generation of children, who can be amazed at the hanging objects in front of them.

That clown is a troll, Brandon--don't feed him.

Brandon has his trollish impulses also.

What always puzzled me about that cat is: why is everybody assumng that the cat cannot observe his own state? What's the darn difference between a human and a feline observer, in quantic mechanics???

I could't agree less.

We will agree to disagree.

Im rusted on this but i think it is simitainesouly alive and dead at the same time intill u open the box and see