186,000 miles per second.
It’s not just a good idea - it’s THE LAW.
Actually, the speed of light is decided upon by international convention, not actual experimental proof.
Seems it varies dependent on how fast a clock one has....
Interesting read if one cares to “ science” it.
Generally, the SOL is figured by a clock and two mirrors, and the “time” lapse between images is averaged....but we all know that makes some unproven assumptions. Anyways, “seeing “ into deep space is not exactly the same as seeing “ back in time”. After all, the light producing the deep space image is making an image “ now” regardless of “when” that light was radiated.