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.

you are viewing a single comment's thread
view the rest of the comments
[โ€“] 1 point 2 years ago

We can and do. GPS satellites need to be regularly calibrated to Earth clock signals or they'll start to drift their calibration by meters per day.

  • source
  • parent