In this web content, the author gives a lightning talk about where computers get their time from. They explain that computers get the time from NTP servers, which in turn get it from other NTP servers, eventually leading to reference clocks like GPS receivers. The author notes that GPS gets its time from Schriever Space Force Base in Colorado, which has the US Naval Observatory Alternate Master Clock. The US Naval Observatory gets its time from atomic clocks and the international earth rotation service. The author also mentions the USNO’s new clock house and the compromise that is UTC. Finally, they discuss the history of time measurement and its connection to the US Naval Observatory and other organizations. Summarizing the talk, the author concludes that computers do not get their time from the Royal Greenwich Observatory.
https://dotat.at/@/2023-05-26-whence-time.html