Most Elegant Equation: Uncovering the Universe

[absurdist]

What is the most beautiful mathematical model that describes the our universe?
It's not just restricted to the pure sciences but also to engineering and applied sciences and math.

If possible, mention an often ignored equation as opposed to the world renowned E=mc^2 for instance.

 

[A.T.]

http://en.wikipedia.org/wiki/Euler's_identity

 

[absurdist]

Wow that really is brilliant thanks!

 

[Claude Bile]

I always thought Maxwell's equations were pretty elegant.

Claude.

 

[genericusrnme]

Poisson brackets

\frac{df}{dt} = [f,H]

Not particularly unknown or anything, they've just got some very nice properties and they serve as a nice segue into QM

 

[absurdist]

I think the beauty comes from the simplicity in appearance as opposed to how much the equation describes about the universe.