Parallel Universes: No longer science fiction

[mad-bax]

What a great thread.

People who pour scorn on Quantum Theory are in good company. Einstein famously remarked "God does not play dice" in reference to Heisenbergs uncertainty principle.

As far as parallel universes go then I would go this far. Physics is based on a set of mathematical models. As such they are all wrong. It is just the extent to which they are wrong that determines how useful they are. For instance you can go from Gallilean relativity, through Newtonian mechanics to General relativity. Each describes spacetime in a useful way. The model you choose for a particular application depends on what you want to do (e.g. drop an object from a set height, describe planetary motion or design a fusion reactor).

What all of these models has in common is that they are all capable of being disproved. Special relativity for instance is based on two assumptions. First, the laws of physics are the same for any observer anywhere in the universe, and second the speed of light is a constant for any observer. If you accept these assumptions then you can develop a model for special relativity on a single sheet of paper using pythag. The model can easily be disproved by showing that either of these assumptions does not hold (and a lot of effort has gone into doing just that).

So when I look at these articles firstly I ask, can I disprove it, or is it just a matter of faith? If it passes this test then I will tentatively accept that although it will definitely be wrong, it may model a phenomenon in a useful way.

Lastly, Bells theorum tells us that we will never know all there is to know about physics anyway.

Now Col is going to tell me just how wrong I am....... He sounds like a clever guy.

Edit: Marginally improved my atrocious spelling and punctuation.

 

[polymath]

Einstein famously remarked "God does not play dice" in reference to Heisenbergs uncertainty principle.

But he was wrong - as some other Physicist (maybe Dirac, or Bohr, or Heisenberg, I can't remember) said:
"Not only does God play dice with the Universe, sometimes he throws them where they can't be seen" (e.g. black holes)

 

[mad-bax]

Yep. Exactly my point. Einstein, great man as he was, was not infallible. OTOH Maxwell has yet to be shown he was wrong...

 

[col]

I tell my students that all Physics is wrong in that sense that none of it can ever be proved correct. It is the job of physicists to construct models that will predict the outcome of future and past experiments. We then perform the experiments and compare. If they disagree, the theory is wrong no matter whether it was Joe Bloggs or Einstein that came up with it. If they agree, we try to find another experiment. We can never prove a theory right. Even if 1 million experimenst agree with the theory we dont know if a new one will show it to be wrong. All Physics theories therefore are just accepted provisionally. So far there are NO experiments which contradict QM despite almost a century of trying.

Einstein had a blind spot about Quantum mechanics. The ironic part is that he won his Nobel prize for the explanation of the photoelectric effect using QM rather than his work on special or general relativity.

Physics is just wonderful. How can anyone not be fascinated by our universe and how it works?

 

[smalltalk]

Well, I really don't think that Everett's Many-Worlds theory is a widely accepted part of contemporary physics.

***

originally posted by col
Einstein had a blind spot about Quantum mechanics. The ironic part is that he won his Nobel prize for the explanation of the photoelectric effect using QM rather than his work on special or general relativity.

I guess, the prize commitee was/is a rather conservative lot and awarding the Nobel prize for SR/GR was too much of a risk if it should all turn out to be wrong after 1921 (IIRC).

Anyway, Quantum theory is a challenge to our mind, mostly because of its probabilistic nature. We do expect probabiltes to stem from a deeper cause. Say, a dice will show each number with p 1/6 because of its symmetric, 6-sided nature. Or in Roulette, the ball will come to a rest at a certain number with 1/37 because a skilled craftsman built the roulette wheel accordingly.

This seems not to be true for QM. mad-bax, would you please elaborate on Bell's inequality? As far as I remember, it states that there are no hidden variables in QM (contrary to the case I stated in the dice example above).

***

I guess, QM is as wrong as Newton's Gravity - both have that spooky action-at-a-distance effect. As long as our two basic theories, QM and GR, are incompatible, there is lots of room for speculation.

 

[Furry Spatula]

I didn't mean to trivialize Quantum Mechanics. What i was refering to is that can you show me empirical evidence that there are multiple universes?

PS. Physics is the branch of science i like the most, Col.

 

[Martacus]

Originally posted by MummyMan
If you want to understand multiple universes, you should read Michael Crichton's Timeline, he has a very simple explanation that uses actual experiments done many times. Of course, with Crichton's books you start to question the validity of some of the things he talks about, obviously its fiction but usually its jsut a fictional storyline based on reality. Check it out, its a good read.

Forget Michael Chrichton, this is a job for Douglas Adams.

 

[alamo]

I am interested in the physics of the universe, but Occam's Razor suggest we perform an experiment and seek the simplest explanation. What exactly was the experiment?

The problem with quantum mechanics is that we are so far removed from the events we are supposedly observing in an unbiased manner. If we smash atomic elements together and observe with a pre-defined set of detectors then we will only see what we want to see. Now we can't build the smashers big enough, not that more alleged primordial particles will make one big happy zoo.

EDIT: Ok, there is no experiment per-se, just a bunch of over-interpreted stellar observations.

So a variation of 70 microkelvins in microwave radiation means either an infinite uninverse, or some unexpected measurement error.

 

[mad-bax]

Smalltalk: I'm not qualified to discuss the inequality in any depth, so instead here is a link to a reasonable explanation

http://www.upscale.utoronto.ca/GeneralInterest/Harrison/BellsTheorem/BellsTheorem.html

IIRC (which I probably don't after 20 years), it is fairly straight forward to obtain probabilities where P <0 or P>1. Since there is nothing in the theorem other than standard "Proven" mathematics which will not allow probabilities outside the range 0<= p<=1 then some QM phenomenon is not behaving in line with our mathematical world. As I say, PLEASE don't take what I say as the truth, I just remember a lecture from university 20 years ago, and the lecturers conclusion was that all of physics can never be known.

 

[Mrogreturns]

Originally posted by polymath
I believe that this universe was created due to some kind of weird 'how d'you do' in higher dimensions ('how d'you do' is a technical term denoting some kind of 'jiggery-pokery')...

Ahh- now I get it