Why does the standard model feature the number 3 so prominently?

[Tanelorn]

A very quick question about the significance of 3:
So we have 3 large dimensions.
And we have 3 generations of quarks.
And we have 3 generations of Leptons.

Is there any known significance or reason or connection to the number 3?
Are there any other examples of sets of 3 in Physics?

https://en.wikipedia.org/wiki/Standard_Model_(mathematical_formulation)#/media/File:Standard_Model_of_Elementary_Particles.svg

 

[fresh_42]

A very quick question about the significance of 3:
So we have 3 large dimensions.
And we have 3 generations of quarks.
And we have 3 generations of Leptons.

Is there any known significance or reason or connection to the number 3?
Are there any other examples of sets of 3 in Physics?

https://en.wikipedia.org/wiki/Standard_Model_(mathematical_formulation)#/media/File:Standard_Model_of_Elementary_Particles.svg

A very quick answer about the significance of $2$:
We have a quadratic electromagnetic force which is all around.
Newtons quadratic gravitation is a pretty good model for everyday experiences.
The normal distribution that is applicable almost everywhere in nature goes with $e^{-t^2}$.
Our entire logic (true / false), ethics (good / bad), spirituality (ying / yang), most of biological processes (reproduction, cell division), computer arithmetic (0 / 1) and so on are all based on two.
Our functions which we use to describe the universe are subsets of a product space $X \times Y$.
There is matter and antimatter, spin up and down, Pauli's exclusion principle - all $2$.

Summary: You could do this for a lot of numbers: $0\; , \;1\; , \;\pi\; , \;e$ or whatever. This doesn't carry any insights and IMO is pure esoteric. You mentioned the standard model, but it's fundamental group so far is $U(1) \times SU(2) \times SU(3)$, so it's $(1,2,3)$ or $(1,3,8)$ depending on how you want to look at it. To pick the three from it is a bit randomly.

 

[anorlunda]

Don't forget the all important number 42 .

 

[sophiecentaur]

Arghhh here comes Numerology again.

 

[phinds]

Arghhh here comes Numerology again.

Exactly. @Tanelorn, you're pissing up a rope on this one.

 

[marcusl]

@Tanelorn, you're pissing up a rope on this one.

That mixes at least two separate metaphors!

 

[phinds]

That mixes at least two separate metaphors!

I don't think so. It's an old military saying. Maybe if it had been 3 ropes

 

[Orodruin]

And we have 3 generations of quarks.
And we have 3 generations of Leptons.

Whereas looking at another arbitrary number 3 is numerology, it is significant that these two numbers are the same (not 3 necessarily) for anomaly cancellation in QFT so I would even say that the OP is just a list of two numbers (not three) that happen to be the same.

 

[marcusl]

It's an old military saying.

That doesn't invalidate my observation...

 

[phinds]

That doesn't invalidate my observation...

I still disagree. Explain yourself, please.

 

[marcusl]

Ok
Just because you heard it in the military doesn't mean that someone (in the military) didn't combine pissing into the wind with pushing on a rope.

 

[phinds]

Ok
Just because you heard it in the military doesn't mean that someone (in the military) didn't combine pissing into the wind with pushing on a rope.

Sounds like you are missing the point completely. This has nothing to do with pushing. Think what happens if you stand under a rope and piss up it.

 

[marcusl]

Ok, we've gotten off topic here. (We won't discuss your ability to stand and piss upwards onto a rope above you ))

 

[Dale]

Although it does seem like the most useful part of the thread

 

[Drakkith]

Are there any other examples of sets of 3 in Physics?

This is so broad that it falls into numerology. If you have a specific question about the relationship between a certain number and a specific concept in physics then feel free to ask, but please try to keep the focus narrow if you want to attract high quality answers.

It appears this thread is done.

Thread locked.