From Aristotle’s “now” to Einstein’s relativity, time has been both a felt companion and a measurable parameter. Equally, every clock is an experiment in turning motion into a countable moment.
- Mechanical clocks count oscillations; atomic clocks count quantum transitions.
- Special relativity shows that simultaneity depends on observers’ motion—GPS satellites compensate for that.
- Civil calendars reconcile continuous cosmic cycles with discrete days, using leap seconds or months.