> Those people that want to drill tunnels through the earth to get better-than-great-circle distances might be the future. Might also get a little warm and yo

> Those people that want to drill tunnels through the earth to get better-than-great-circle distances might be the future. Might also get a little warm and you'd fight a lot of pressure, since you'd need to dig down about 1/3rd of the distance you'd want to save (assuming my elementary geometry memories aren't failing me). So to save 600km distance, you'd have to go down to a max depth of almost 200km. For context, the deepest bore hole drilled to date seems to be about 12km deep. [0] So technology would have to improve a lot before global warming or the next meteor get us all. [0] https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole