Then I tell them light is like sound, only much faster. It has finite speed.
The moon is two light seconds away. We see it two seconds in its past. Same with the Sun, only it’s eight minutes away. Then I move to the planets and then to whatever is in the eyepiece, usually a star. Then I pull up Stellarium and tell them how far that star is away (in time.).
Edited by Neptunus Rex, 28 September 2023 - 01:14 PM.