Carl Sagan explains how the Ancient Greeks knew the Earth was round [video]

Bizarre: the original 4:3 video has been put into filled-in letterboxed vertical video (!), and then YouTube shows it pillarboxed, for a full windowboxed video!

https://en.wikipedia.org/wiki/Letterboxing_(filming)

I think I can guess why: the black letterboxing one would get without the top and bottom fillers might be off-putting for people watching on their phones. And no detail is lost since the original had such low resolution for modern standards.

I still think it’s a net benefit if this brings Cosmos to more people even if it looks horrid to me, and this particular cut is a very good standalone explanation and illustration of the concept.

Too bad this method didn't find its way into Netflix "Behind the Curve".