# Probability and quantum possibilities

1. Jan 13, 2013

### NanaToru

So this might be a too simplistic question on many accounts.

My pchem professor said to us that in QM, anything that can happen will. And it's a matter of probability, right?

I guess I'm just curious what the scales are for something like, say, walking through a wall (the go-to example for a lot of popular science books on QM)? Like, 1 in a billion or what?

2. Jan 13, 2013

### Drakkith

Staff Emeritus
Not quite. It says that anything that can happen, well, can happen. (It is not guaranteed to happen) Yes it is a matter of probability. But don't take this to mean that all of reality and life is probability. Even if it is you don't live your life in fear that every particle in your body is going to quantum tunnel in random directions at the same time.

1 in a billion ^1023. Actually I don't know the right number, and I doubt anyone actually does, but I guarantee it to be so large it is effectively incomprehensible.

3. Jan 13, 2013

### DrChinese

The likelihood of that happening is so low that the universe is far too young for that to be an outcome.

At least, most likely. You never know, maybe something like that has happened.

4. Jan 13, 2013

### soothsayer

That number probably does the odds some justice. I remember calculating the probability of jumping and tunneling all the way to Jupiter, and it was like $e^{10^{10^6}}$ or something. I don't even remember now.

It should be noted that anything that can happen will happen with enough time. Even the probability above says that if the universe lasts long enough, a tunneling event of that magnitude should likely happen.

5. Jan 13, 2013

### Drakkith

Staff Emeritus
My god that's an enormous number.

6. Jan 14, 2013

### soothsayer

It may have been smaller, I can't remember now XD It was definitely e^10 to a really big power, but it may have been closer to 100 than one million. At that point though, what's the difference, really? It's not gonna happen, lol.