The right hand rule is simplistic (as the direction is arbitrary); however, using physical laws (assumed to be universal) is the way to, I think. Even if the al

The right hand rule is simplistic (as the direction is arbitrary); however, using physical laws (assumed to be universal) is the way to, I think. Even if the aliens wouldn't understand our concept of left and right, if they are sufficiently advanced, their physical theories should contain the concept of symmetry (the mathematical concept, not the colloquial one), see this PSE questions and answers: http://physics.stackexchange.com/questions/2690/what-is-the-symmetry-which-is-responsible-for-conservation-of-mass http://physics.stackexchange.com/questions/2690/what-is-the-.... Once that commonality is established we can start to explain to them the everyday concept of symmetry and how we give different names to different directions of symmetry.