2 added 542 characters in body edited Nov 17 '14 at 4:35 nexolute 58133 silver badges99 bronze badges Could it be thatCould it be that the Earth is round, so the bird just gonna fly in parallel with the diameter of the earth to reduce the distance to 5 mph. Edit: Analysis to completely trashed this idea of mine. Suppose the radius of Earth is round$$R=6371\mathrm{km}$$. To obtain the arclength $$C=6\mathrm{m}$$, sowe need to travel $$\theta=6/6371000=9.417\times10^{-7}\mathrm{rad}$$. So if the bird just gonna fly in parallel withto the diameter of the earthEarth, it will be $$L=2R\sin{(\theta/2)}=5.999\mathrm{m}$$. If you use common sense and think about this physical world, this should be obvious too. Maybe I've not been going out to reduce the distance to 5 mphreal world for too long, and I lost my common sense about the world. Probably. Could it be that the Earth is round, so the bird just gonna fly in parallel with the diameter of the earth to reduce the distance to 5 mph. Could it be that the Earth is round, so the bird just gonna fly in parallel with the diameter of the earth to reduce the distance to 5 mph. Edit: Analysis to completely trashed this idea of mine. Suppose the radius of Earth $$R=6371\mathrm{km}$$. To obtain the arclength $$C=6\mathrm{m}$$, we need to travel $$\theta=6/6371000=9.417\times10^{-7}\mathrm{rad}$$. So if the bird fly parallel to the diameter of the Earth, it will be $$L=2R\sin{(\theta/2)}=5.999\mathrm{m}$$. If you use common sense and think about this physical world, this should be obvious too. Maybe I've not been going out to the real world for too long, and I lost my common sense about the world. Probably. 1 answered Nov 17 '14 at 3:50 nexolute 58133 silver badges99 bronze badges Could it be that the Earth is round, so the bird just gonna fly in parallel with the diameter of the earth to reduce the distance to 5 mph.