I disagree. It's interesting to me that the data from the observers provided this information:

"Everyone above 96th Street saw the moon completely covering the disk of the sun, though no one below 96th street was able to do so. That experience represented a victory in measurement: The eclipse’s southern border could be pinpointed to within 225 feet, or the distance between 230 Riverside Drive and 240 Riverside Drive. The shadow’s border was literally caught between two buildings, each on its own city block."

Aren't the movement of the earth and sun so predictable that we could have simulated this outcome to a similar degree of accuracy?

Experiments like this are how you confirm whether or not your predictions are accurate.

I scrolled straight to the bottom to try it out. I kept tapping the button and it’d appear for a split second and disappear. It took me a few tries to realize that it’s not a button and requires tap-and-drag (I’m on mobile). I suspect I’m not the only one that would have this issue.

I haven’t seen this kind of “non-button button” before. Is this a common UX choice?

iOS has that ever since Force Touch. You could peek and either abort by releasing or pop it into existence as an overlay by pressing further until first haptic feedback (second one would navigate to instead of overlay), then move through menu entries and select an entry by releasing without lifting the finger.

It was super quick to use and I really enjoyed it, especially in Music.app e.g to quickly build listening queues from a list of tracks.

Nowadays they dialed down on that paradigm (probably because of drag and drop support mostly) but you can still find it in some places (e.g home screen icons)

I find it a bit more awkward than before though because the popping is now time-based ever since Force Touch was dropped at the hardware level.

(Damn how I liked Force Touch, the irony is I realised how much I valued it only ever since it disappeared. The force-touch anywhere on the keyboard to turn the whole screen in a caret moving surface was so much better than today's long-pressing space in subtle but very tangible ways)

Force touch was the single most undiscoverable UX ever invented. Wonder how many iPhone users upgraded their devices multiple times without ever realizing it's a thing.