Feynman suggested shining polarized light through a solution of glucose and water. This will rotate the plane of the polarization clockwise. https://en.wikipedia.org/wiki/Glucose#History
Cool, I didn't know that! The glucose molecule has a handedness though, which means it has a rotationally symmetric twin L-Glucose [1] with the same properties. The relative abundance of glucose over l-glucose is purely a property of which one life on earth happened to choose (they're not biologically compatible). So if you communicated blueprints for life on earth including glucose without an absolute rotation reference, the aliens could reconstruct everything two ways: biology with our glucose, or biology with l-glucose, and there's no way to differentiate between them since they would both work the same.
Veritasium makes a great video about symmetries that's very relevant here [2], and might suggest a slightly more practical way to correctly communicate handedness to aliens. The full CP violation experiment isn't necessary, as long as we assume that the aliens live in a universe made of mostly matter (as opposed to antimatter) like ours, and we can communicate the parity violation experiment (~measuring the preferential atomic decay direction of cobalt atoms near 0K in a magnetic field [3]), they should be able to reconstruct an absolute reference for rotation.
Veritasium makes a great video about symmetries that's very relevant here [2], and might suggest a slightly more practical way to correctly communicate handedness to aliens. The full CP violation experiment isn't necessary, as long as we assume that the aliens live in a universe made of mostly matter (as opposed to antimatter) like ours, and we can communicate the parity violation experiment (~measuring the preferential atomic decay direction of cobalt atoms near 0K in a magnetic field [3]), they should be able to reconstruct an absolute reference for rotation.
[1]: https://en.wikipedia.org/wiki/L-Glucose
[2]: https://www.youtube.com/watch?v=yArprk0q9eE
[3]: http://www.physics.utah.edu/~belz/phys5110/PhysRev.104.254.p...