[sonnekki]

> Noon should always be noon

In other words, given a point on Earth (or any planet) and it's angle relative to the sun it orbits, when that point aligns exactly with and faces the center of the sun, it is noon.

Consider this: The way everyone refers to time is "X Units before noon", much like the 24-hour clock (no am/pm), except 0 is noon. The key is that X must be flexible, it should have no maximum, and no minimum.

edit: clarification

[T-hawk]

This is not literally true. The period between solar noons oscillates and varies up to tens of seconds away from precisely 12 hours, thanks to the differing orbital speed of the Earth between perihelion and aphelion. What you're referring to is "mean noon", true solar noon averaged over the course of a year. See "mean sun" : http://en.wikipedia.org/wiki/Mean_sun

More complications arise from the position of the Moon. The Earth's rotation is affected by tides (stronger when the Moon is at perigee), and by the Earth's orbit around the Earth-Moon barycenter. Precession of the Earth's rotational axis is also a factor. And many more astromechanical effects also subtly affect the timing of the apparent position of the Sun.

Locking our timekeeping to the actual position of the Sun actually proves to be an intractable problem. At some point, we need abstractions to simplify and assume that that the relation to the Sun is good-enough. Famously, the Julian calendar was good-enough for millennia until the relation to the sun drifted off true by more than 10 days. So arguing over leap seconds could be seen as rather trivial.

[sonnekki]

This is amazing stuff. Thanks! I agree that arguing over leap seconds is trivial. We're at a good enough point now, assuming leap seconds are handled correctly, such that accounting for those seconds keeps us on track.

[draz]

reminds me of "relative time" Jews and Muslims (and Japanese, until 1872) use. This is a French wikipedia article I stumbled upon: http://fr.wikipedia.org/wiki/Shaot_zmaniot