"Time was a problem. Time was always a problem. "It started, she had learned, with the fact that **simultaneity was an illusion, and “the same time” on different planets in different systems was mostly an accounting convenience that only functioned because most people were moving relatively slowly compared to lightspeed**. But beyond that, the measurements of time were embedded in history. An hour had sixty minutes because mathematicians in ancient [[Babylon]] had worked in a sexagesimal system. A year was the time it took Earth to make a full transit around Sol, and that mattered even though Teresa had never been to Earth and almost certainly never would. **Like the number of minutes in an hour, the width of a centimeter, the volume of a liter, the length of a year was the marker by which humanity told the story of itself.**" --- **Tags** -- [[quotes]], [[units-of-measure]], [[physics]] **Source** -- [[20250424114419 - B - Leviathan Falls]]