The difference lies primarily in their scope and nature: a coordinate system is a mathematical tool spanning all of spacetime, while a frame (or reference frame) is a physical entity that moves and occupies a finite space, often serving as the origin for the coordinate system.
Based on the provided information, here's a breakdown of the distinction between these concepts:
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Coordinate System: This is a comprehensive mathematical framework used to specify points in spacetime. According to the reference, a coordinate system has the capacity to span all of spacetime. It provides the axes and units needed to assign numerical values (coordinates) to events or locations.
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Frame (Reference Frame): This refers to something that moves. Unlike a coordinate system that spans everything, a frame is a localized, physical entity that occupies a finite space.
Key Distinction:
The crucial link, as highlighted in the reference, is that the origin of a coordinate system is something that moves. This "something that moves" is precisely what the reference describes as a frame.
In essence:
- A coordinate system is the grid or mapping that covers spacetime.
- A frame is the moving viewpoint or physical entity from which measurements are made, often associated with the origin of the coordinate system.
Think of it this way: You can have a coordinate system for the entire Earth (spanning vast space), but your car is a moving frame within that system. Your car occupies a finite space and moves, and you could set up a local coordinate system originating from your car to describe things relative to it.
