4 ms·
The only thing that is missing here is that the different lengths don't matter by themselves. The explanation could be that the rays of the sun are not parallel
by hervature 5y ago
The only thing that is missing here is that the different lengths don't matter by themselves. The explanation could be that the rays of the sun are not parallel. Of course, this would put the sun closer than the moon but we are assuming we cannot use extraterrestrial knowledge. To complete the logic, you need to measure in multiple locations and note that the shadows do not change as expected if there was no curvature of the earth.
- giomasce 5y agoTotally true. More in general, it is a relatively simple mathematical fact that a sphere without a point is homeomorphic (even conformally!) to a plane. Therefore, it is impossible to prove that the Earth is spherical unless you either do measurements and run numbers (like you propose) or visit every single location of it (including all the seas and both poles; particularly the south pole, which for some reason flat earthers tend to assume it is missing). The only way to do the latter, as far as I can tell, is to be in a sufficiently polar orbit for enough time (or at least have a satellite in orbit), and few people are able to do that (directly, i.e., without trusting somebody else). It is interesting that is not uncommon for flat earthers to be more "scientific" that many spherical earthers in recognizing that many spherical Earth arguments are not sufficient by themselves. Of course the spherical earthers happen to be right, while the flat earthers then proceed to invent completely implausible theories to support their beliefs, but they deserve some recognition for the first stage.