I take the scientists word for it in the meantime as I always have, but I'm still unsure how to prove it is not a spinning coin without seeing the stars or sun.

I shall give you an experiment to do without seeing the sun or shadows.

Go to a tall tree, or building where there is a fair amount of visibility, perhaps in a park.

Then note how far you can see, then climb up the tree and note how far you can see again. Even with the smog, you should be able to see further when you're higher up the tree than on the ground.

This proves that the earth is curved....

Cg