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.
Here’s something I just ran into looking stuff up for my comment: GN-z11 is one of the farthest galaxies we’ve ever seen. Thanks to the expansion of the universe, at a distance of over 30 billion light-years, it has to be moving away from us at over twice the speed of light.
What the fuck does that mean, temporally? Like, forget the speed of light, time dilation has to do with space and relative speeds. If I’m moving at near the speed of light relative to you, then my clock will physically tick more slowly. What happens if I’m moving over twice the speed of light? Is the real life GN-z11 in our reference frame moving backwards in time at over twice the rate we’re moving forward?
From my understanding, this is caused by the universe itself expanding between the 2 objects, not that the object itself is moving that speed relative to us. It’s still completely insane to think about, either way.