Fun fact about the Photosphere: We have no idea why it works like it does, or what's really going on there.
Okay that's not actually that fun. But there's lots to explore and figure out. I think my favorite currently open mystery is this one. In general, the closer you are to a heat-emitting object, the hotter it gets, right? Common sense. Holding your hand far from the stove is cool, closer to the stove is hot, and on the stove is yeowch. But... that isn't exactly true in the Photosphere. As you go up, there are "layers" that are HOTTER than the ones beneath them, closer to the core of the sun. WTF?! How is this even possible?