4 ms·

What I find surprising is that the number of generations is fixed. When I first read about particle generations, my reaction was 'oh yeah, it's obviously the sa

What I find surprising is that the number of generations is fixed. When I first read about particle generations, my reaction was 'oh yeah, it's obviously the same particles in some higher energy state, so it should keep going up indefinitely.' But no, it stops at three generations? I have no idea why that would happen.

nsns 11y ago
But don't all essential components of nature seem random/unexplainable from our point of view? While we can codify their behavior and interrelations via some theory, it never actually explains why they are so and there in the first place.
- TheOtherHobbes 11y ago
  Kind of. There's certainly an interest in finding precise models that are mutually supportive and self-consistent. So the "Why?" question can be answered with "Because that's the only way the whole thing can work." Unfortunately it's just as likely that "Because randomness" is a valid answer. Right now, no one knows. (Although IMO randomness isn't really an answer, because randomness can only happen as the result of a process. It isn't a thing in itself. So I'm always wary of anything that says "It's just random" without explaining how and why it got to be that way.)
- krastanov 11y ago
  I believe that you would enjoy reading "The Unreasonable Effectiveness of Mathematics in the Natural Sciences". It is a short essay that deals (but does not answer) the question of why "some theory" that "never actually explains why" seems to still work? https://www.dartmouth.edu/~matc/MathDrama/reading/Wigner.html https://www.dartmouth.edu/~matc/MathDrama/reading/Wigner.htm...
Analog24 11y ago
It's not really correct to think of them as only differing by their energy state. The second and third generations of quarks (strange/charm and bottom/top) have additional quantum numbers, flavor quantum numbers, that also need to be conserved. In addition, a defining characteristic of the strong force, as described by QCD, is the existence of the well known phenomenon called Asymptotic Freedom [1]. Based on the theory of QCD this is only possible if there are no more than 8 generations of quarks (16 flavors in total). Granted, we are only aware of three generations at the moment but this does put an upper limit on the total number of possible quark generations. I know this isn't the most satisfying answer to your question but I just wanted to point out that there are some well known differences and bounds on the number of quark generations. [1]: https://en.wikipedia.org/wiki/Asymptotic_freedom https://en.wikipedia.org/wiki/Asymptotic_freedom

nsns 11y ago

But don't all essential components of nature seem random/unexplainable from our point of view? While we can codify their behavior and interrelations via some theory, it never actually explains why they are so and there in the first place.

TheOtherHobbes 11y ago
Kind of. There's certainly an interest in finding precise models that are mutually supportive and self-consistent. So the "Why?" question can be answered with "Because that's the only way the whole thing can work." Unfortunately it's just as likely that "Because randomness" is a valid answer. Right now, no one knows. (Although IMO randomness isn't really an answer, because randomness can only happen as the result of a process. It isn't a thing in itself. So I'm always wary of anything that says "It's just random" without explaining how and why it got to be that way.)
krastanov 11y ago
I believe that you would enjoy reading "The Unreasonable Effectiveness of Mathematics in the Natural Sciences". It is a short essay that deals (but does not answer) the question of why "some theory" that "never actually explains why" seems to still work? https://www.dartmouth.edu/~matc/MathDrama/reading/Wigner.html https://www.dartmouth.edu/~matc/MathDrama/reading/Wigner.htm...

Analog24 11y ago

It's not really correct to think of them as only differing by their energy state. The second and third generations of quarks (strange/charm and bottom/top) have additional quantum numbers, flavor quantum numbers, that also need to be conserved. In addition, a defining characteristic of the strong force, as described by QCD, is the existence of the well known phenomenon called Asymptotic Freedom [1]. Based on the theory of QCD this is only possible if there are no more than 8 generations of quarks (16 flavors in total). Granted, we are only aware of three generations at the moment but this does put an upper limit on the total number of possible quark generations. I know this isn't the most satisfying answer to your question but I just wanted to point out that there are some well known differences and bounds on the number of quark generations. [1]: https://en.wikipedia.org/wiki/Asymptotic_freedom https://en.wikipedia.org/wiki/Asymptotic_freedom