Brussels / 31 January & 1 February 2015


Precise time: from CPU clocks to hacking the Universe

Adventures of a time nut

Time is the most precisely measured quantity we have, yet it is still the most mysterious. Precise time and frequency are the hidden ingredient in most technology used today, from computer synchronization, to satellite navigation, to data communications, to digital music and video. In this talk we explore the amazing world of precise time, a world that anyone with curiosity can explore on their own.

It is not uncommon for ham radio operators, electrical engineers, or physicists to encounter the details about precision timing. But it turns out that playing with computer hardware and operating system software is also a wonderful entry into the obscure world of nanoseconds and parts per million accuracy.

The talk is in three parts:

  • Examples of precise time and frequency in computing, from operating systems to microcontrollers.
  • A "powers of ten" tour of clocks, timekeeping, and measurement; from the worst possible clock you can find at home to the best atomic clock you can buy.
  • The results of Project GREĀ²AT, a DIY time experiment where Einstein's general theory of relativity was demonstrated by carrying atomic clocks from home up a mountain and the predicted time dilation actually measured. This puts keeping accurate time on a new level, and makes one wonder what time really is.


Photo of Tom Van Baak Tom Van Baak