# Is nature symmetric?

## Main Question or Discussion Point

I guess that nature do not care about "directions". If i'm performing an experiment on (for example) light the result is invariant on the direction of the laboratory.
So why we observe directionality on the nature that we are observing around us?
Why "things" are definitively not symmetric? When the universe "was created" when and why it have taken a specific space direction?

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Drakkith
Staff Emeritus
If i'm performing an experiment on (for example) light the result is invariant on the direction of the laboratory.
What is 'the direction of the laboratory'?

When the universe "was created" when and why it have taken a specific space direction?
I don't know what this means. The universe cannot move, only objects within the universe can move.

Just to be clear...if i have a lab here on earth oriented to south the Maxwell equations (for example) are true if it is oriented to north the Mawell equations are still true and they have the same form. So nature does not have a preferred spatial direction. So why my home, for example, is facing North? Why it is not completely symmetric. Somewhere, sometime some physical phenomena have cleared displayed a preferred direction, why?

Drakkith
Staff Emeritus
I don't think there's an answer to that. That just seems to be the way the laws of nature work.

ok

Dale
Mentor
The laws of nature take the form of differential equations. In order to find a solution to a differential equation you need both the law and also a set of boundary conditions. Even if the law is symmetric a solution may be asymmetric if the boundary conditions are asymmetric.

Such is the case with your house. Maxwells equations do not pick out a North oriented house, but rather the boundary conditions do. As a result, even though Maxwells equations treat all directions the same, one side of your house will receive more light energy than another.

the house was just a metaphor...but supposing the problem to be true...why the BC are not symmetric? the problem is not solved but only transfered.

Dale
Mentor
Why would you assume that the boundary conditions should be symmetric? This isn't a problem to be solved, just a mistaken assumption to correct.

I'm not talking about any pratical engineering problem. I'm just saying that space does not have any preferred direction, since no experiment, performed ideally, can spot in which direction we are pointing (just like the velocity, no experiment can say if we have speed or not...(some people say that velocity does not even exist for this reason)).
So, ASSUMING that space and the matter inside have evolved from a symmetrical state...when and why was the symmetry violated?

Dale
Mentor
I'm not talking about any pratical engineering problem.
Me neither. I am talking about the form of the laws of physics.

So, ASSUMING that space and the matter inside have evolved from a symmetrical state.
That is a bad assumption. The boundary conditions are not symmetrical.