Reminds me of another Scifi book called "Light of Other Days" by Bob Shaw in which the story uses the idea of "slow glass": glass through which light takes year

Reminds me of another Scifi book called "Light of Other Days" by Bob Shaw in which the story uses the idea of "slow glass": glass through which light takes years to pass. https://en.wikipedia.org/wiki/Light_of_Other_Days https://en.wikipedia.org/wiki/Light_of_Other_Days