I was also confused by the article, but I've noticed that I'm not the only one. I think I get what confused the author, it's the fact that angle the shadow appear to us depends on the latitude of the viewer on Earth. It's not super intuitive.
tiborsaas · · focus · HN ↗
<a href="https://www.youtube.com/watch?v=XHzzRbw0lgI" rel="nofollow">https://www.youtube.com/watch?v=XHzzRbw0lgI