What’s something most people don’t understand?

There’s a lot about astronomy I don’t know. There is a branch of science known as astrophysics for instance that is about light speed and gravity, red shifts, dark matter, black holes, dark energy, pulsars , neutron stars, the list is enormous.

I do try and understand some of this, there has been a TV programme on the BBC for decades called the Sky at Night. I’ve watched it since childhood. That sparked an interest and we did have a cheap  telescope for a while. I’ve seen Jupiters moons through it and Saturns rings.

I’m amazed though at web pages about flat earth believers. Some of the things that they post are very odd and nonsensical. I don’t understand how incredibly silly some of them are! No offence meant but they worry me.