The original question was: Relative to the size my feet appear when I’m standing up and looking at the ground, how large would Australia appear if I could see all the way through the Earth and observe its shape? There’s a seriously old theorem from the days when togas meant math (not frat parties) called the “inscribed angle theorem”. Which means that, if you could see it through the Earth, it would take up about 17° of your vision. Unless you’re in Australia. Unless you’re on the beach or something (90°?).