But it isn’t a mystery at all. The moon is moving away from us. For billions of years the moon’s apparent size was larger than the sun. For billions of years later it will appear smaller. It’s simply a lucky coincidence we live in this moment in time, in that regard.
That isn’t clear at all and I’m not even sure I agree, regardless. Hydrostatic equilibrium is a regularly occuring thing. No, I’m not looking up how regular. The Universe is mind-bogglingly enormous and everything is unusual. Have a good day.