Apart from that the sun and moon are really far away and that you can clearly see why the moon phase is what is it because of how it is orientated in relation to the sun, just because the sun is setting for your perspective doesn't mean the moon is is going to be looking "down" on the sun
The light from the sun comes to us from far enough away that even at the earth-moon distance it’s reasonable to model the rays as parallel. They’ll be illuminating the earth-moon system in a roughly similar way, but from our perspective inside that system on a rotating earth the position of the sun on our horizon doesn’t correlate to the overall position of the sun with respect to both.
It’s because we look at a 3D world with 2D retinas and our brains do a lot of processing to try and make everything look straight and rectangular. Which is nice if you are living in a box. But when there are no straight lines for reference, your brain can’t make sense of it. That nice “straight” horizon you’re looking at is actually a circle which stretches behind you. Your poor brain is trying to process this raw data projected onto our retina (which btw is also a portion of a sphere ) . The whole thing is a mind fck tbh. It forces you to accept that in many ways the “reality” we perceive isn’t real. I hesitate to even call this an optical illusion…we are experiencing a constant illusion and when we look up and see curved lines in space connecting the moon’s terminator with the sun we think something is broken.
PoppersOfCorn t1_j4dl3j5 wrote
Apart from that the sun and moon are really far away and that you can clearly see why the moon phase is what is it because of how it is orientated in relation to the sun, just because the sun is setting for your perspective doesn't mean the moon is is going to be looking "down" on the sun