Just to preface, I believe everything that we were taught in our physics about the physical laws of our reality is completely factual, except for the concept of gravity
Its really only the concepts that we are taught about "outer space" that I question
We can prove concepts like force, potential energy, kinetic energy, rate of transfer etc through experimentation. There's no way for me to personally prove that what we see in the sky are solid objects
The first time I started to really question what we're seeing in the sky was during one of my astronomy classes at GT. We went to one of the observatories at night to observe and study the moon through one their many high powered telescopes. I can still remember how when I looked at the moon through the telescope, the moon didn't look like a solid object to me AT ALL but I kept that to myself. I didn't get into flat earth stuff until after GT and the only reason I did was to try and definitively DISPROVE flat earth theory
Then I realized that I couldnt