So let me say thank you for posting this. I do like a SUBSTANTIVE conversation.
I agree that the multiple FE threads is getting kind of crazy. I didn't realize there were so many when I posted my Biblical Cosmology one. Now I'm getting lost as to where I posted stuff.
Another user actually posted this same Professor Dave video in... I think the BIG flat earth thread. Here is my answer to him:
1. Challenge 1: Show a scale that works on an AE map. This is an impossible challenge. Firstly, let me point out that in the northern hemisphere, the globe and the AE map do differ, but the differences are not as pronounced as the variance between the HUGE southern hemisphere of the AE map and the southern hemisphere of the globe which is the same size as the northern. Dave cunningly says you can "make a scale, then test it in your car." Sure. Easily, on a local level WITHIN a continent. But you cannot test a scale (realistically) in a vehicle over great distances if you are a poor normal human being, and the GPS system is gatekept by the establishment, so you cannot use any kind of digital technology to verify, prove, or disprove anything here.
2. Challenge 2: Explain the amounts of night and day. This has actually been done. The problem here is that flat earth is not cohesive and different flat earthers each have their areas of exploration and expertise. Also, we are trying to build an entire system of thinking with extremely limited resources and have been doing this less than a decade. So there's that. But look up something called "coffee cup caustics." This stuff is fascinating. In a reflective (say, stainless steel) coffee cup, a single point light source can be caught by the reflective perimeter and "wrapped" around the entire periphery while leaving only a spot of darkness in the middle. The motion of the Sun inwards and outwards between the tropic of capricorn and the tropic of cancer, as well as consideration of a coffee cup caustic effect from a firmament dome, can explain seasons and extended periods of light or darkness perfectly, even around the entire Antarctic periphery all at once while still leaving darkness in the middle. You should look up pictures of "sun dogs" as well if you have not seen this phenomenon before.
3. Challenge 3: Make any prediction whatsoever. Dave is missing something big here. A lot of things work literally exactly the same on a flat earth as on a globe. Compass navigation. Star positions. I mentioned in another post that planetariums and astronomical software essentially use a flat earth presentation system. Ironically, Dave mentions eclipses as proof of heliocentricity. He shows an image of an eclipse shadow path that actually is a big problem for the globe model. How can a gigantic moon cast a shadow on the earth that is only dozens of miles across? Also, eclipses are not predicted using the heliocentric model at all. Their cyclical nature has been recorded for millennia and encapsulated in a system called the Saros cycle. Completely independently of the shape of the earth, it simply predicts the timing of eclipses. NASA has a resident Saros cycle expert who handles their eclipse predictions. A flat earther could use the Saros cycle to predict an eclipse as well... and the shadow path size actually makes sense for a small, local moon. Here's another thought to chew on: the heliocentric model PREDICTS that the sun and moon should never be visible in the sky at the same time during a lunar eclipse. After all, if both are in the sky... what's casting a shadow on the moon? This happens all the time, though. It's called a selenelion. Conveniently, magic refraction bends light so we see what we see, according to the globers.