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There is a simple experiment to show curvature that was actually done by some flat earthers, and it proved curvature, but then they somehow classified it as an

by GTP 5y ago

There is a simple experiment to show curvature that was actually done by some flat earthers, and it proved curvature, but then they somehow classified it as an interesting but not conclusive result. Here's the experiment: take 3 wood planks, make a hole at the same eight in each of them. Then put them standing in the soil making sure that all have the same height (meaning that the hole is at the same height for all of them). Now use a laser to have a straight line of light (you can observe by other means that a laser beam is a straight line). If the wooden planks are far enough form each other, the laser will not e able to pass trough all 3 holes, despite them being at the same height from heart's surface. This implies curvature.

dalmo3 5y ago
That's too prone to terrain irregularities, and I can't imagine that there's a single area of land on earth that's remotely as smooth as the surface of an sphere. Further, even if you assume perfect instrumentation, how would one account for gravity?
- zimpenfish 5y ago
  > I can't imagine that there's a single area of land on earth that's remotely as smooth as the surface of an sphere Salar de Uyuni - "As a result, the variation in the surface elevation over the 10,582-square-kilometer (4,086 sq mi) area of Salar de Uyuni is less than 1 meter (3 ft 3 in) normal to the Earth's circumference". That's less than 1 in 6371000 - pretty smooth, no? > That's too prone to terrain irregularities Nah, it's still doable, especially on that^ salt flat - if you have two close holes and a 3rd one 55km away, a flat earth will let you line up the laser through all three with less than 2m of adjustment. By my rough calculations, on a spherical earth, the laser will be ~250m above ground at 55km - pretty obviously proving the hypothesis incorrect, no?
  - dalmo3 5y ago
    That's a great example, thanks!
- GTP 5y ago
  Sorry, I fail to see what would be the problem with gravity here. Do you mean we should consider that gravity curves the laser beam?

by GTP 5y ago

dalmo3 5y ago

That's too prone to terrain irregularities, and I can't imagine that there's a single area of land on earth that's remotely as smooth as the surface of an sphere. Further, even if you assume perfect instrumentation, how would one account for gravity?

zimpenfish 5y ago
> I can't imagine that there's a single area of land on earth that's remotely as smooth as the surface of an sphere Salar de Uyuni - "As a result, the variation in the surface elevation over the 10,582-square-kilometer (4,086 sq mi) area of Salar de Uyuni is less than 1 meter (3 ft 3 in) normal to the Earth's circumference". That's less than 1 in 6371000 - pretty smooth, no? > That's too prone to terrain irregularities Nah, it's still doable, especially on that^ salt flat - if you have two close holes and a 3rd one 55km away, a flat earth will let you line up the laser through all three with less than 2m of adjustment. By my rough calculations, on a spherical earth, the laser will be ~250m above ground at 55km - pretty obviously proving the hypothesis incorrect, no?
- dalmo3 5y ago
  That's a great example, thanks!
GTP 5y ago
Sorry, I fail to see what would be the problem with gravity here. Do you mean we should consider that gravity curves the laser beam?