3 ms·
Defining time based on "sun directly overhead at a particular place at noon" is, itself, a holdover from navigation and seafaring. The time difference between w
by ThrustVectoring 12y ago
Defining time based on "sun directly overhead at a particular place at noon" is, itself, a holdover from navigation and seafaring. The time difference between when the sun is directly overhead where you are and directly overhead at a particular place is the latitude difference between the two places.
That's the historical reason why we have a time definition that is locked to the rotation of the Earth. Importantly, anyone navigating based on that principle will get skewed answers if when noon is at a particular place changes.
- gpvos 12y agoInteresting; do you have a source for that? I'd have thought that it would be most useful for people on land, too, to have noon at a well-defined time.
- ThrustVectoring 12y agoIt's not a question of moving noon around by hours, but moving noon around by minutes or seconds. It's not sourced since it's what I remember off of navigational history. Whether solar noon is at 11:45 or 12:15 makes little difference for your personal life, but observing solar noon at 11:45 vs 12:15 is a difference of 1/48th the way around the globe longitudinally.