For me it is the fact that our blood contains iron. I earlier used to believe the word stood for some ‘organic element’ since I couldn’t accept we had metal flowing through our supposed carbon-based bodies, till I realized that is where the taste and smell of blood comes from.
Time relativity always boggles my brain, I accept the fact but I find crazy that if I strap my twin and his atomic clock to a rocket and send them out to the stratosphere at the speed of light, when they return he’ll be younger than me and his clock will be running behind mine. Crazy
Light is something else. If you were a photon, your existence wouldn’t be any measurable amount of time. You’d pop in and out of existence at the same time. Not only that, but your destination would be right where you popped into existence. Point being, photons do not experience time or distance. Only us outsiders do. If you managed to travel at the speed of light, from your perspective your destination would be right where you are and you’d get there instantly. Only contact with the outside world would confirm how far you traveled and for how long.
Also the idea that light is both a particle and a wave always mess with my head because I wanted to know why does it decide to change and when? And the answer is that light is always a particle and always a wave at the exact same time.
It is a wave particle.
And it is possible from light alone to build both an electron and a positron as demonstrated in a 1999 laser science experiment in New York.