Is there a point to this post?
Yes. It is that those who plan and build these exploratory space probes must plan for environments never before considered. The important aspect is that the 'space' in our Universe is not uniform. If we can design probes to survive these different environments, we may find out about other differences, such as gravity and the speed of light.
We assume the speed of light is constant, and base our measurements of distances to the stars with it. Outside of our galactic cluster, things may be different.
(just trying to imagine the scale of our 'galactic cluster' completely blows my mind.)