A 1cm light source at a height of 100cm cannot "produce day" on an entire football field, and those are just arbitrary dimensions.
There's a law for this, you don't seem to be aware. Here an interesting presentation how it also disproves your space dreams and also debunks any moon landing claims:
https://odysee.com/@GLOBEBUSTERS:c/globebusters-bob-knodel-2019-feic:1
Doesn't open, Odysee sucks.
Anyway, no matter what height you put the light at, it will never produce night on HALF of the plain.
You will always have a gradient of light encompassing the entire plain, but no night.
In order for you to have a defined twilight line, and night on half of the plain, you'll need a shade around the source of light.
It sucks because there's no mommy to cry to when you see a video you don't like. This presentation is removed from youtube.
Yes, I agree - a small light will shine light on the entire world 😆
