3 ms·

What other approaches are there that wouldn't lead to a quantum theory of gravity?

by ndsipa_pomu 3y ago

trhr 3y ago
[flagged]
- quickthrower2 3y ago
  Are you hinting at infinitesimals?
  - trhr 3y ago
    No, those are fine. Well, almost. They're not uniquely broken, at least. Mathematics would have me believe "the sum of all positive integers" is a negative number. They can provide glorious proofs of that fact. When you insert the result into the physics equations, the equations work. But the idea is, on its face, stupid. Any child would tell you as much. The equations only "work" on that premise because they're almost right. But that's not a problem with infinity, it's a problem with something we're assuming when we go to write the proof in the first place. And whatever that problem is... it's almost certainly the thing stopping us from solving the Riemann hypothesis.
- ndsipa_pomu 3y ago
  There's more than one "math" system and Riemann Spheres allow division by zero. How does that help visualise the universe?
  - trhr 3y ago
    Oh, you mean the system that defines pi to be infinity minus infinity? That's the one that's correct? Okay, good luck with that.
    - dang 3y ago
      Can you please stop posting unsubstantive comments and definitely please not post in the flamewar style to HN? You've done that a lot in this thread and it's not what this site is for. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
- tnecniv 3y ago
  You could define the Big Bang to be at any value of t, i.e., pick t0 > 0. Such a shift changes nothing and won’t fix any singularities in the dynamics.
  - trhr 3y ago
    You, by definition, cannot. Our best science suggests that `t` ceases to be a linear value at t=0. It's why we define t=0 to be there. The problem is the absurdity of the idea that `t` could ever cease to be a linear value. Causality is a fundamental truth. To lose the idea of "before" and "after" is to lose causality. If your fundamental theorem of the universe requires you to forego causality, you should consider looking elsewhere.
- Attrecomet 3y ago
  This is literally just a string of buzzwords connected to form a grammatically correct sentence.
  - trhr 3y ago
    Goedel, Russell, and Frege proved from first principals that our understanding of basic arithmetic cannot be both complete and consistent. One or the other, but not both. If children's arithmetic cannot be proven complete and consistent, what does that say about the sort of math used to define the universe? Building upon a broken structure is how you get broken results.
- mhh__ 3y ago
  Ironically zero is the only number unlike any other number.
  - trhr 3y ago
    Fair. I misstated my premise. "Find the math that allows zero to be treated like any other number, or, find the math that treats it like it's definitely the wrong answer." Consistency is the key. What we have now is only locally consistent. You can break it into pieces with set theory, geometry, etc. You're never going to find a unifying equation in a version of mathematics where geometry and algebra don't mesh.
uoaei 3y ago
There is more focus of late on theories of "emergent gravity", i.e., that gravity is not a fundamental force. The most interesting one to me is so-called "entropic gravity", which also resolves the issues plaguing the theory of dark matter and gives credence to MOND. Such theories have been long derided by old-school physicists raised in the golden era of quantum mechanics (and their acolytes), but have surprisingly powerful explanatory power that other theories cannot achieve without tacking on seemingly arbitrary or else otherwise unmotivated factors. Dark matter especially has always been suspect to me, since even after all this time, it is defined as little more than "the gap between our models and observations" with no strong underpinnings that would explain its existence in satisfying ways. I am not affiliated with this blog in any way but find the arguments compelling: https://tritonstation.com/ https://tritonstation.com/ Here's an interview with a researcher who is also trying to move beyond quantum formalisms for spacetime vis a vis gravity: https://www.quantamagazine.org/the-physicist-who-bets-that-gravity-cant-be-quantized-20230710/ https://www.quantamagazine.org/the-physicist-who-bets-that-g...

What other approaches are there that wouldn't lead to a quantum theory of gravity?

trhr 3y ago

[flagged]

quickthrower2 3y ago
Are you hinting at infinitesimals?
- trhr 3y ago
  No, those are fine. Well, almost. They're not uniquely broken, at least. Mathematics would have me believe "the sum of all positive integers" is a negative number. They can provide glorious proofs of that fact. When you insert the result into the physics equations, the equations work. But the idea is, on its face, stupid. Any child would tell you as much. The equations only "work" on that premise because they're almost right. But that's not a problem with infinity, it's a problem with something we're assuming when we go to write the proof in the first place. And whatever that problem is... it's almost certainly the thing stopping us from solving the Riemann hypothesis.
ndsipa_pomu 3y ago
There's more than one "math" system and Riemann Spheres allow division by zero. How does that help visualise the universe?
- trhr 3y ago
  Oh, you mean the system that defines pi to be infinity minus infinity? That's the one that's correct? Okay, good luck with that.
  - dang 3y ago
    Can you please stop posting unsubstantive comments and definitely please not post in the flamewar style to HN? You've done that a lot in this thread and it's not what this site is for. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
tnecniv 3y ago
You could define the Big Bang to be at any value of t, i.e., pick t0 > 0. Such a shift changes nothing and won’t fix any singularities in the dynamics.
- trhr 3y ago
  You, by definition, cannot. Our best science suggests that `t` ceases to be a linear value at t=0. It's why we define t=0 to be there. The problem is the absurdity of the idea that `t` could ever cease to be a linear value. Causality is a fundamental truth. To lose the idea of "before" and "after" is to lose causality. If your fundamental theorem of the universe requires you to forego causality, you should consider looking elsewhere.
Attrecomet 3y ago
This is literally just a string of buzzwords connected to form a grammatically correct sentence.
- trhr 3y ago
  Goedel, Russell, and Frege proved from first principals that our understanding of basic arithmetic cannot be both complete and consistent. One or the other, but not both. If children's arithmetic cannot be proven complete and consistent, what does that say about the sort of math used to define the universe? Building upon a broken structure is how you get broken results.
mhh__ 3y ago
Ironically zero is the only number unlike any other number.
- trhr 3y ago
  Fair. I misstated my premise. "Find the math that allows zero to be treated like any other number, or, find the math that treats it like it's definitely the wrong answer." Consistency is the key. What we have now is only locally consistent. You can break it into pieces with set theory, geometry, etc. You're never going to find a unifying equation in a version of mathematics where geometry and algebra don't mesh.

uoaei 3y ago

There is more focus of late on theories of "emergent gravity", i.e., that gravity is not a fundamental force. The most interesting one to me is so-called "entropic gravity", which also resolves the issues plaguing the theory of dark matter and gives credence to MOND. Such theories have been long derided by old-school physicists raised in the golden era of quantum mechanics (and their acolytes), but have surprisingly powerful explanatory power that other theories cannot achieve without tacking on seemingly arbitrary or else otherwise unmotivated factors. Dark matter especially has always been suspect to me, since even after all this time, it is defined as little more than "the gap between our models and observations" with no strong underpinnings that would explain its existence in satisfying ways. I am not affiliated with this blog in any way but find the arguments compelling: https://tritonstation.com/ https://tritonstation.com/ Here's an interview with a researcher who is also trying to move beyond quantum formalisms for spacetime vis a vis gravity: https://www.quantamagazine.org/the-physicist-who-bets-that-gravity-cant-be-quantized-20230710/ https://www.quantamagazine.org/the-physicist-who-bets-that-g...