The Null Geodesic-printing

The ideal example of a "null geodesic" is by definition a "line of sight" light ray, free of any interference from any intervening gravitational fields, especially over unlimited regions of cosmic spacetime.

Hence the "null geodesic" is the mathematical equivalent for a pure Newtonian straight-line in 3-dimensional Euclidean geometric space.

To allow or block links to the Internet in PDFs: https://helpx.adobe.com/acrobat/11/using/allow-or-block-links-internet.html