1. thirdwind
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    thirdwind Contributing Member Contest Administrator Reviewer Contributor

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    Let's talk physics

    Discussion in 'The Lounge' started by thirdwind, Dec 6, 2013.

    I'm sure there are at least a few of you here who enjoy reading about physics and discussing it with others, which is why I created this thread. I've been reading up on random physics stuff whenever I get the time. I never realized how fun physics can be once you take the math out of it. :p

    Anyway, most of the reading I've done is on wormholes and how they could theoretically be used to travel between universes. It's an interesting thought, though I'm not sure how realistic or feasible this is even in the distant future. What are your thoughts on this? Also, are there any topics within physics that you find particularly interesting?
     
  2. Andrae Smith
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    Andrae Smith Gone exploring... in the inner realm... Contributor

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    This is a good idea for a thread, but I fear discussion of theory may quickly turn into:
    "Sorry kiddo, that's a nice idea, but that could never happen."
    "But what if bla bla bla..."
    "No, if you have any basic understanding of the principle you'll see..."
    "Well I do understand it but I think it might be able to work if..."
    "Well you're still wrong because you'd have to assume everything we know is wrong."
    "What if it is?"
    "It's not. We have evidence."
    "But we don't know everything."
    "We know enough because the math and tests are consistent."
    "But we could discover..."
    "No! The facts don't change. I trust facts not wacko theories."
    "Don't gotta be mean"
    "I'm not, this is science."

    I hope I'm wrong, but I'll come back when I have more time or when there's more up (whichever comes first). I don't know enough about what I've been looking into to defend it anyway. :p
     
  3. 123456789
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    123456789 Contributing Member Contributor

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    I'll bite. Anti matter is amazing. It's pretty beautiful that its existence was derived mathematically (negative energy solution to Dirac equation for spin 1/2 particles, eg. electrons) and then only later proved experimentally. It's fundamental significance to the Universe is obvious, though what that is exactly is beyond me to say. It does suggest (to me) some sort of symmetry, at least in principle, to the Universe. The question of why the Universe appears to favor matter over Anti Matter is a big one.

    Then, of course, you have all the sci fi stuff about it too.
     
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  4. thirdwind
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    thirdwind Contributing Member Contest Administrator Reviewer Contributor

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    @Andrae Smith, hopefully that won't happen. I also hope people don't start bringing God or religion into this.
     
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  5. AJC
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    AJC Active Member

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    Math is the language of physics, and if you don't understand the math, then you won't be able to fully understand or appreciate the physics. That being said, I certainly don't expect the average person to learn all the math. I like that you're taking the time to read some of the literature that's available.

    All of this comes from solutions to Einstein's equations. However, even though the math makes sense, the answer may not make sense for real life applications. The problem is that we have no way of knowing. For now, all of this is just theory and speculation.

    I could write an entire list, but I will mention two topics that I spent a number of years doing research on. They are quantum computing and information theory.
     
  6. AJC
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    AJC Active Member

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    This is a tough question for sure, and I know that there's a lot of debate about this in the astrophysics community. I've attended lectures and seminars from particle physicists, cosmologists, and even a theoretical physicist, and they all had different theories.
     
  7. thirdwind
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    thirdwind Contributing Member Contest Administrator Reviewer Contributor

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    Thanks. Upper level math is tough for me. Just looking at the Schrodinger equation makes my head spin. Anything basic I can understand, however.

    Isn't that the problem with string theory? From what I understand, the math works well, but the theory has no observational evidence to support it.
     
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  8. Cogito
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    Cogito Former Mod, Retired Supporter Contributor

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    That's exactly how scientific theories always evolve. Mathematical models are proposed to explain a discrepancy arising from established models. The new equations are examined to see what they predict for conditions not yet measured, and an effort is made to see how accurate those predictions are. Often, it takes considerable ingenuity to find ways to measure or even detect the predicted effects.

    A theory which has no predictive value beyond already measured phenomena is not useful.

    Or not... :D

    Sorry, I literally laughed out loud when I read that, given the relationship of the equation to electron orbitals.
     
    Last edited: Dec 6, 2013
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  9. Cogito
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    Cogito Former Mod, Retired Supporter Contributor

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    double post, pls delete
     
  10. 123456789
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    123456789 Contributing Member Contributor

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    Wasn't black body radiation observed first and described second?
     
  11. Cogito
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    Cogito Former Mod, Retired Supporter Contributor

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    Qualitatively observed. It wasn't until Planck's equations that it was quantitatively understood, and only then was it understood that it could also apply to radiating sources other than ordinary matter, that it was a fundamental thermodynamic property.
     
  12. AJC
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    AJC Active Member

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    LOL! That's a good one. Is your head spin up or spin down? ;)

    String theory has some qualitative observations to support it. For better evidence, you would have to go to higher energies, smaller length scales, or both. The beauty of string theory and a lot of modern theories is that it gets rid of the idea of particles. In fact, quantum mechanics, which deals with particles, is just a limiting case of quantum field theory, which is a very popular theory among physicists, though the public doesn't seem to know about it at all. QFT replaces particles with fields, and what we think of as particles are in fact just excitations of various fields. It's worth reading about.
     
  13. thirdwind
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    thirdwind Contributing Member Contest Administrator Reviewer Contributor

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    I had to look up what spin up and spin down are. But I get it now! :D

    That seems like a weird idea. Why is this better than quantum mechanics (or any theory involving particles)? Is it because of more accurate results?
     
  14. Cogito
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    Cogito Former Mod, Retired Supporter Contributor

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    How strange... Do you live a charmed life?
     
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  15. Patra Felino
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    Patra Felino Active Member

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    Physics just gets weirder and more counter-intuitive the deeper you go. It's fairly easy to understand as long as you're looking at roughly normal sizes (i.e. not sub-atomic or star-sized), speeds (i.e. near light speed) etc.

    But if you think about what we would have historically used our intuition for (that woolly mammoth would flatten me if it ran into me/that lava looks hot so I should avoid falling into the volcano/that looks slippery so be careful!) you can understand why it's so hard to imagine a single particle going through two different slits at the same time, or things getter heavier as they approach light speed. There's no reason to expect stuff to feel right anymore because the things happening on these scales are, in effect, outside our realms of experience.
     
  16. Simpson17866
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    Simpson17866 Contributing Member Contributor

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    I love this site :) Whole thing, top to bottom.
     
  17. We Are Cartographers
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    We Are Cartographers Active Member

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    .
     
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  18. AJC
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    AJC Active Member

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    It makes things easier when you're dealing with a system where the number of particles are changing. It also better explains particle decay, where one particle is decaying into several other particles. In QM, there's no explanation for why a neutron would decay into a proton, an electron, and an antineutrino. QFT explains this through the oscillations of the various fields.

    Lol. Those are good ones.
     

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