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What Is Space?

nautil.us

151–155 of 155 posts

Re: What Is Space?

#151
post #142

Earlier quoted context omitted.

> The rest of your post is discussing philosophy, I'm trying not to be philosophical and wondering if by now we have enough data so that we can talk about purpose without being philosophical. Sure, that we have that much data now is a long shot! > What makes you think it was deliberate? It looks like it might be a deliberate case of our being denied information that might let us see behind the curtain, that is, see m…

Alright, I'm just going to focus on the physics in your comment. > How we get from special relativity to that, I want to check out in detail. It's a fairly trivial derivation once you get past the fact that Newtonian mechanics doesn't work at relativistic speeds (the big insight Einstein had was his conviction that Maxwell was correct and Newton was wrong). You do it in second-year physics courses (at least, that's w…

For EPR, as I understand it from my too crude reading, there is an event and two particles are created and fly off in different, maybe from conservation of momentum, opposite directions. So, the two particles are a QM system with one wave function which, however, is in two parts that are separating rapidly.

As I understand the usual interpretation of the wave function, there is no, say, definite spin. We don't know what the spin of either particle is, and neither does the wave function or anything else. That is, a definite value of the spin just doesn't exist yet.

Then we measure the spin of one of the particles, and that measurement gives us a spin that apparently was determined just at our measurement. Then the wave function of the two particles has to change, and the other particle has its wave function but if we measure its spin we will get what we are supposed to, say, opposite, from what we measured from the first particle. So, the fixing of the spin of the particle we measure second was somehow transmitted faster than the speed of light. Just what was transmitted faster than the speed of light we don't know about, can't detect, and is not physics in any usual sense. Still, say, if we were trying to write a computer program to simulate this, as soon as the first measurement was made, we'd have to stop the simulation clock of the universe, go the other particle, on the simulation clock, infinitely fast, fix that particle's spin, and then continue the simulation. Strange stuff.

But, sure, that doesn't tell us how to do communications with EPR "spooky action at a distance".

I don't yet know enough QM to make well informed questions about more. I should watch the MIT QM course lectures through to the end (hold my nose on how he does his math) and pick out the more important things they are saying about how wave functions behave, when there are interactions and the wave functions disappear, etc.

Yes, pretty much need to assume the axiom of choice, and some of its consequences are tough to swallow.

> Again, currently we do not have a way of predicting the outcome of an individual experiment, but there's no reason to believe that we will never be able to do so.

Right. So, if we could so predict, what surprising things could we do with that? So, we are being forbidden to do such things. Why? Does this provide a clue about purpose? Right, this is a long way from physics at least now.

For why SR says that information cannot be transmitted faster than light, IIRC what you said about the Lorentz transformations can say that just information, of any kind, sent any way, known to current physics or not, would permit a case of time travel or seeing into the future or some such, and we don't want to believe in that.

Yes, there is physics, say, the standard model, and first cut it looks quite simple. But the consequences are astounding beyond belief. E.g., we couldn't look at the standard model and see how DNA would work and what it would do, for green plants, earth worms, ..., humans. Heck, just looking at the standard model, we might guess that the universe would be just a fog of hydrogen or something else so simple. Even if we looked at the standard model long enough to conclude that galaxies and stars would form, some stars would explode and create some of the periodic table (the rest created otherwise), condense to planets, it's still tough to see why the planets would be more than, say, just Mars. But, no, DNA happened and after a billion or so years, we happened. That looks so astounding it looks suspiciously like part of a purpose. But you are right, that's not physics yet.

Re: What Is Space?

#152
post #144

Earlier quoted context omitted.

While a careful review of the foundations is valuable, and there's always a chance to find something others have missed, honestly it sounds like you're missing the physical intuitions a lot more than the maths. When I read what you wrote, thinking about unitarity came later; the immediate instinctive thought below even the level of language was "wrong, the wavefunction doesn't do that". I guess it depends what you wa…

I know about unitary in math. Just what QM does with it I don't know yet! I'm eager enough to further develop my intuitive understanding. My ugrad physics prof said I had "a good feeling for physics" -- that was after I blew away everyone else in his freshman physics class!! :-) Yes, being careful can yield new results in old fields. I've published two papers that apparently did that, one paper in optimization and th…

> I do get the impression that quite a lot about QM is still a bit fuzzy to nearly everyone.

I have the opposite experience; QM is really very clean, coherent, elegant, and well-understood - far more so than GR, I found. The people who want it to work like classical physics get themselves (and anyone who listens to them) awfully confused, but that confusion goes away, and you get a much better appreciation for what QM does if you put aside the "big questions" for a while and do some concrete computation. At least that's how it worked for me.

Re: What Is Space?

#153
post #55

Earlier quoted context omitted.

google interviews try to gauge how smart you are, not how well you can program

If you don't test a candidate how good a programmer they are, you shouldn't be too surprised when you end up hiring a lot of bad programmers.

Does Google tend to get a lot of bad programmers?

Re: What Is Space?

#154
post #131
post #94

Earlier quoted context omitted.

> And such a wave function doesn't split just once but commonly many times. So, the one, poor photon as one simple wave function is soon in dozens of pieces all moving away from each other usually never to come together again. After a billion years, the pieces are still moving away from each other. > Then, presto, bingo, one part of that wave function enters our telescope and hits our detector. Then all the dozens of…

> There are a dozen different possibilities for what the photon has done - a dozen different universes, if you like. As long as the photon never interacts with anything else, this bundle of a dozen universes can act much the same as a single universe. Certainly if you're just looking at a telescope, all dozen versions of that telescope are behaving the same, so they behave like a single unified instance. Well that's…

> If what you said is possibly true, then light could be a carrier of things like multi-dimensional spin, or possibly where dark matter really comes from (inter-dimensional interference).

That's a total non-sequitur. What on earth are you talking about?

Re: What Is Space?

#155
post #55

Earlier quoted context omitted.

If you don't test a candidate how good a programmer they are, you shouldn't be too surprised when you end up hiring a lot of bad programmers.

Does Google tend to get a lot of bad programmers?

If you are hiring tens of thousands of employees, its impossible to expect all will be top of the line.

My guess is Google has plenty of bad programmers, or worse Imposters.

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