Читать книгу String Theory For Dummies - Andrew Zimmerman Jones - Страница 91

If an object has translational symmetry, you can move it and it continues to look the same (for a detailed explanation of this, flip to Chapter 4). Moving objects in space doesn’t change the physical properties of the system.

Now, didn’t we just say in the last section that the potential energy due to gravity changes depending on where an object is? Yes, we did. Moving an object’s location in space can have an impact on the physical system, but the laws of physics themselves don’t change (so far as we can tell). If the Empire State Building, Earth, and the penny held over the edge (the entire “system” in this example) were all shifted by the same amount in the same direction, there would be no noticeable change to the system.