Cosmology and Geometry (3)
It is often simpler to discuss things happening in the expansion of the Universe
if we adopt a vantage point that is moving uniformly with the expansion.
Astronomers call such a vantage point a comoving coordinate system.
Comoving Coordinates
The following animation illustrates a simple comoving coordinate system.
The essential idea of such a system is that the coordinates of the points do not change under
expansion of the scale, but distances do. The change in distance is simply due to the scale
expansion in this case.
