I’m thinking of things like heliocentrism where there was some modern discovery or revelation by science that invalidated a common assumption prior.
My understanding is that flat earth is more a recent phenomena but I’d love to hear some ancient ideas people now miss. Did people think trees weren’t alive? Did people think evaporation was where things simply disappeared?
I’d would love to hear these ideas.
Not exactly a scientific debate, but among the general public there was strong opposition to the idea that rocket engines would work in space, where there’s “nothing to push against.” Famously, the New York Times editorial board mocked Robert Goddard (the rocket scientist that now has a NASA space flight center named after him) in a 1920 article:
Image of the editorial
The New York Times eventually formally retracted that op ed, on July 17th, 1969 - while the Apollo 11 crew was already en route to the moon. The retraction is pretty funny:
Retraction source