# Thread: You will live forever, whether you want to or not.

1. Note an interesting (and might I add a bit disturbing) aspect of this theory is the problem of quantum suicide, which states that even suicide attempts will fail to completely kill you! You are, however, still very likely to end up in a worse condition than where you started with each attempt.

2. There's an old short story by Larry Niven that deals with these ideas - it's called All The Myriad Ways.

3. Originally Posted by JimD
There's an old short story by Larry Niven that deals with these ideas - it's called All The Myriad Ways.

I'm on the last few pages of a book called 'Brasyl" by Ian Macdonald that deals with multiverses. Good storyteller - complex ideas.
I also recently read 'River of Gods" by same author - story takes place in India in 2047 and also deals with alternate universes a company attempts to build generator that uses quantum mechanics to pull energy from other universes. Also a very good read if you like the near future genres.

4. Thanks! I'm not familiar with those authors; I'll have to check them out.

5. According to Everett's thesis, and Bohm and DeWitt's work that followed it (see, DeWitt, B. and Graham, N., "The Many Worlds Interpretation of Quantum Mechanics", Princeton Series in Physics, Princeton Press, 1973)., the "Many Worlds" interpretation of quantum mechnics states something like the following:

Suppose I have a combined system of two states. For instance, I toss a coin that lands on my hand and I cover it with my other hand so that I don't know the result. Thus, I have not made a "measurement". I can have two states, heads or tails, (actually I can have a third, the coin could have landed on its edge, but let's disregard this for the momment). The probability function for the state just before I uncover the coin (make a measurement) is P(X + Y) where X = heads and Y = tails is the combined wavefunction for the event. Note that both states must exist before I make a measurement otherwise the whole notion of a probability would fail. This is not the same as P(X) + P(Y) which is what you might expect. These would be valid after a measurement. According to Everett, when I uncover the coin the Universe splits into two Universes, one in which the wavefunction "collapses" into the "head" state and one in which the wavefunction "collapses" into the "tail" state. His arugment is that since each state is equally probable, an outside observer, watching the event must see both events because to the outside observer both outcomes are also equally probable and so, before the outside observer makes his/her measurement, both states must exist as well. Thus, when I toss a coin and measure the results I create two Universes, one in which I measured "heads" and the other where I measured "tails". The fact that I don't experience both states simultaneously is due to the fact that they are mutually orthogonal results. If I were to calculate the expectation value of both events occurring simultaneously I would get <Heads|Measurement|Tails> = 0 because the basis vectors of the wavefuctions are orthogonal. Depending upon which Universe I'm in I would either get <Heads|Measurement|Heads> = 1 and <Tails|Measurement|Tails> = 0 or <Heads|Measurement|Heads> = 0 and <Tails|Measurement|Tails> = 1.

So the "Many Worlds" interpretation says that anything that can happen happens.

In the cartoon, if I were next to a nuclear explosion, the interaction of the atomic blast and the atoms in my cells would create a vast number of possible states. Since they are all possible, Everett states that they actually occur so there would be a vast number of me's, most of which I died in, but there is at least one universe that I surrived the blast. Of course, there would be other Universes in which I would be partially destroyed or totally destroyed but I wouldn't experience them all. Most likely I'd experience one of the states in which I "died".

Technically, just to confuse the issue further, it could be argued that I experience all of the possible Universes. The fact that I am only conscience of one of them is due to the orthogonality of my wavefunctions. There may very well be many of me in many Universes, even though I am only conscience of one of them at any time, even though I have many other consciences. BTW, this means that in some other Universe I am walking around perfectly fine -- in fact -- I'm a great athelete. I bet that other Universe feels great.

6. Originally Posted by StarLord
Technically, just to confuse the issue further, it could be argued that I experience all of the possible Universes. The fact that I am only conscience of one of them is due to the orthogonality of my wavefunctions.
wat??

7. A nuclear explosion is like hooking a party balloon up to an air hose. As you turn on the air the balloon expands. The shape is spherical. In no universe, (no matter how unlikely that universe is) will that balloon ever have any other shape than a ball. This is because the particles eminating from an exposion are set on their way having first interacted with each other in order to find a spare piece of tragectory to occupy.

But hey...that's just a detail.

8. Originally Posted by MarkB701
A nuclear explosion is like hooking a party balloon up to an air hose. As you turn on the air the balloon expands. The shape is spherical. In no universe, (no matter how unlikely that universe is) will that balloon ever have any other shape than a ball. This is because the particles eminating from an exposion are set on their way having first interacted with each other in order to find a spare piece of tragectory to occupy.

But hey...that's just a detail.
Mark, I am not sure that I agree. Not all universes need to agree with the principles of physics that we observe in ours. But, even in our current universe, there are many situations where the blast from a nuclear explosion may not be spherical. For example, if the explosion were to occur next to a black hole, one would expect all matter and therefore most radiation to head in the direction of the gravity sink.

Wise.

9. Originally Posted by Wise Young
Mark, I am not sure that I agree. Not all universes need to agree with the principles of physics that we observe in ours. But, even in our current universe, there are many situations where the blast from a nuclear explosion may not be spherical. For example, if the explosion were to occur next to a black hole, one would expect all matter and therefore most radiation to head in the direction of the gravity sink.

Wise.
True. However, since the question involves a human being being killed, I was working using 2 assumptions:
1) laws of physics extend to the furthest possible reaches of human travel
2) explosion is in an area of uniform(ish) matter (by which I include standing in the air on the face of a planet).

Regardless, I like your post, since I had not thought that far out of my box.

10. Originally Posted by MarkB701
True. However, since the question involves a human being being killed, I was working using 2 assumptions:
1) laws of physics extend to the furthest possible reaches of human travel
2) explosion is in an area of uniform(ish) matter (by which I include standing in the air on the face of a planet).

Regardless, I like your post, since I had not thought that far out of my box.
Mark, if I were your physics professor, I would still be shaking my head. A nuclear explosion anywhere close to the surface of the earth (or any mass) would not be spherical. Whether on the surface of the earth or a mile from the surface of the earth, the nuclear blast would be hemispherical. How to protect a human being in close proximity to a nuclear blast is in fact a real engineering problem that has to be solved by designers of bomb shelters.

But, let us consider the problem that was posed, i.e. whether a person could possibly survive a nuclear explosion. What is the probability that particles from an adjacent nuclear explosion would pass through a body without striking enough of the atoms in the body to kill the person? The probability is small but not infinitely small. Depending of course on the intensity of the explosion and the distance, that probability is probably not much smaller than the chances of winning a lottery and yet many people buy lottery tickets, thinking that they will be lucky.

In reality, we are mostly empty space. As Sir Arthur Stanley Eddington once put it, matter is almost all empty space. In fact, 99.9999999999999% of matter is empty space. If you were to pack all the people on earth together so that there is no empty space, that compressed ball of humanity would be no larger than a grain of rice (Source). Given that there is this much space in us, it is perhaps not so inconceivable that somebody might survive standing next to the nuclear explosion.

Wise.

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