• Question: how is time measured, and how do you know?

    Asked by KNE:):) to Jonny, Paul on 26 Jun 2015.
    • Photo: Paul Brack

      Paul Brack answered on 26 Jun 2015:

      Here is a great article which describes the development of time measurement from ancient times to now: http://nrich.maths.org/6070. We now use atomic clocks to measure times – these use the energy change in electrons when you fire microwaves at them to keep time to a very, very accurate level,

    • Photo: Jonny Brooks-Bartlett

      Jonny Brooks-Bartlett answered on 26 Jun 2015:

      Just to add, Einstein said that time is relative and really there is no concept of “absolute time”. I.e. time is different for each person depending on how fast they’re moving (weird I know).

      So really time is something that we’ve made up. There’s much more to it than that but then you’re going into stuff I don’t know about.